State diagram aluminum zirconium. Dual Chart - Status
When zirconium dioxide is introduced into the electrolysis bath, an aluminum-zirconium alloy should be formed. The ongoing alloy formation has a significant impact on the course of the entire technological process and, first of all, on the electrochemical separation of aluminum. In addition, since the reduction of zirconium dioxide dissolved in the electrolyte is possible both electrochemically and aluminothermally, it is necessary to consider the effect of alloy formation on a possible shift in the zirconium precipitation potential, as well as on the course of the aluminothermic reduction reaction. The absence of difficulties in the electrochemical reduction of aluminum in the presence of zirconium will allow the process to be carried out with energy costs close to those in the production of aluminum. At the same time, due to the low solubility of ZrO2 in cryolite-alumina melts, the completeness of the reaction of aluminothermic reduction of zirconium dioxide is essential, which makes it necessary to estimate the residual concentration of ZrO2 in the electrolyte. To solve these issues, it is necessary to have information about the thermodynamic properties of the resulting aluminum - zirconium alloys. A characteristic feature for zirconium, expected on a liquid aluminum cathode, is its chemical interaction with aluminum. As follows from the state diagram, it can form a number of solid compounds with aluminum. This, in turn, will in a certain way affect the physicochemical properties of the resulting ligature, affect the technology of the electrolysis process. The state of the general theory of metal alloys and, in particular, the theory of metal solutions, does not allow calculations of the thermodynamic properties of master alloys based on data for pure aluminum and zirconium. Setting up experiments to study the thermodynamic characteristics of alloys containing zirconium and aluminum is very difficult due to their high chemical activity, and therefore the data available in the literature are far from complete. In the work of Yu.O.Esin and coworkers, the heats of mixing of liquid alloys of aluminum with zirconium were determined by the calorimetric method in the concentration range from 0 to 60% at.Zr. The data obtained are presented in Table 3.1. The data presented in Table 3.1 indicate that very large deviations from Raoult's law are observed in the melts of the Al-Zr system. A decrease in the absolute values of DHZr and DHAl with an increase in the concentration of zirconium or aluminum in the alloy indicates a strong interaction of zirconium with aluminum. In other words, the Al-Zr bond is much stronger than Al-Al and Zr-Zr. The strong interaction of these two elements is also evidenced by the state diagram of Al-Zr, in which congruent compounds are formed that melt without decomposition. Similar formations of aluminum and zirconium atoms are also preserved in liquid alloys even at high superheats relative to the liquidus line. For a complete thermodynamic characterization of alloys, it is necessary to have the values of the activities of the components in the alloy. To determine the thermodynamic properties of alloys, several methods are mainly used: the method of measuring the saturation vapor pressure over the alloy; calorimetric method and method based on the determination of the distribution coefficient, the method of electromotive forces.
Double phase diagrams limiting the zirconium angle have been investigated.
Composition and mechanical properties of technical hytan (GOST 9853 - 61. | Influence of some elements on the strength of Ti. All known double phase diagrams of alloys based on Ti are divided into three large groups according to the nature of the liquidus and solidus lines near the Ti ordinate (approximately 30 - 40% of the weight alloying additive), and each of these groups - into subgroups according to the nature of transformations in the solid state.
Composition and mechanical properties of technical titanium (GOST 9853 - 61. | Influence of Sn and AI on the tensile strength of titanium alloys. All known double phase diagrams of Ti-based alloys are divided into three large groups according to the nature of the liquidus and solidus lines near the Ti ordinate (approximately 30 - 40% by weight of the alloying additive), and each of these groups - into subgroups according to the nature of transformations in the solid state.
The similarity of double phase diagrams and the same crystal structure of niobium, tantalum, molybdenum, and tungsten and the resulting silicides predetermine the similarity in the patterns of formation and structure of the diffusion layer.
The nature of the double state diagrams of metals of groups V-VI or in a broader aspect of groups III-VIII and the patterns observed in these systems are primarily due to the proximity of the electronic structure of the outer shells of their atoms.
An analysis of double state diagrams of refractory transition metals of groups IV-VI with interstitial elements (B, C, N, O) shows that, as a rule, the metal component forms a eutectic with the nearest intermediate compound. Such systems are characterized by a relatively low solubility of interstitial elements in the base metal (see Fig. 38), which increases with increasing temperature. In multivalent, strongly ionizing metals of IV-VI groups, the valence electrons of interstitial impurities are collectivized and therefore the solubility of B3, C, N3, O4 ions is determined by the ratio of atomic radii rx / rm.
When constructing double state diagrams, the composition of the alloy is plotted along the horizontal axis in percent, and along the vertical axis - the temperature in degrees Celsius. Thus, each point of the diagram corresponds to a certain alloy composition at a certain temperature under equilibrium conditions.
It is convenient to use such a series of double state diagrams when analyzing the influence of the nature of the interaction between soldered metal A and solder B on their compatibility. In such a consideration, it should be taken into account that state diagrams characterize the phase composition of alloys and the composition of alloy phases under equilibrium conditions.
Diagram of a closed region of austenite.| Diagram diagram with continuous solubility of Fe a (8 and alloying element. | Diagram diagram with continuous solubility of t - iron and alloying element. | Expanded, limited region of t - solid solution. A feature of all double state diagrams of iron with other elements is the presence of recrystallization in solid state due to polymorphic transformations of iron.Modifications a and b have the same lattice of a body-centered cube.In the temperature range (910 - 1401) there is a y-modification, which has a cube lattice with centered faces.
The segment rule in dual statecharts can only be applied in two-phase areas. In a single-phase region, there is only one phase; any point inside the region characterizes its concentration.
The segment rule in dual statecharts can only be applied in two-phase areas.
These questions are answered by the dual state diagrams shown in FIG.
The answer to these questions is given by the double diagrams of the state of titans - an alloying element, presented in Fig. 374 as a classification scheme.
The answer to these questions is given by the double state diagrams of titanium - an alloying element, shown in Fig. 374 in the form of a class diagram.
Solder metals and solder metals forming double state diagrams, the components of which are insoluble in each other in either the liquid or solid state (see Fig. 4) or are sparingly soluble in the liquid state, but insoluble in the solid state (see Fig. 4) can only form adhesive-type joints.
On fig. Figures 58 and 59 show double state diagrams of aluminum with copper and magnesium. In both cases, with increasing temperature, a significant change in the solubility of alloying elements in aluminum is observed. A similar change in solubility is observed in multicomponent systems, which makes it possible to strengthen heat treatment. However, in complex alloys, phases with complex composition and structure will be in equilibrium with an aluminum solution according to the corresponding phase diagrams.
Outwardly, vertical section diagrams are similar to double state diagrams. Only the liquidus and solidus curves do not intersect in the general case on the ordinates of the vertical sections.
It summarizes new data on 1719 double phase diagrams and crystal structures of phases, published in 1957 - 1961, as well as old works not reflected in the handbook.
To characterize phase equilibria in cast irons, double state diagrams are primarily used.
Analysis of the structure of lead babbits should be carried out based on the double state diagram Pb - Sb (Fig.
Outwardly, the section diagram (Fig. 117) is similar to a double state diagram. The difference is that instead of a eutectic horizontal, an area e a c appears in the cut in the form of a triangle, the sides of which are curved lines formed at the intersection of the cut plane with the ruled surfaces of the three-phase volume.
The surfaces of the onset of crystallization of double eutectics pass through the corresponding eutectic horizontals of double state diagrams.
It is easy to see that the discussed section does not really have the properties of a double state diagram, since it contains, in addition to equilibria with phases 8 and y, equilibria in which the phase (3) is represented, which is released from the liquid in the region above the temperatures of formation of a solid solution of the compound and turning into the last one.
Variant of the state diagram shown at 468 when the V - fl section becomes partially double.| Variant of the state diagram depicted in 469 when the VtA resolution becomes partially doubled. Between points A and p, this cut has all the properties of a double state diagram. Beyond the point r, it contains elements of the state that are not directly related to the AVZ system, and therefore loses the properties of a binary system in this part of it.
Therefore, the 22-year period that elapsed between the first and second editions of the Dual State Diagram Handbook would now be invalid. Anderko, the US Air Force Space Laboratories 1 were asked to support the publication of this handbook.
Phase and structural changes occurring at the diffusion stage of the process can be predicted using double state diagrams if only two elements are involved in the diffusion interaction. It is assumed that the diffusion process is not intensified and the resulting diffusion zone is in an equilibrium state.
Using the method of vertical sections of a triple state diagram, let us follow the example of the discussed diagram for a gradual transition from a double state diagram of one type to a double state diagram of another type.
Zirconium angle of the state diagram of the zirconium - vanadium - nickel system. At a temperature of -770 there is a eutectoid four-phase equilibrium p6 ta3 Zr2Ni ZrV2, which is formed from the second-class equilibrium P2 - B4 - Zr2Ni ZrV2 departing from the above four-phase equilibrium and two eutectoid equilibria p4 a1 Zr2Ni and P53 a2 ZrV2, coming from the corresponding double state diagrams.
In order to determine the joint effect of niobium and aluminum on the properties of zirconium, work was undertaken to study the triple state diagram of a part of the zirconium-niobium-aluminum system rich in zirconium. In the double state diagram of the zirconium-aluminum system in the temperature range from 1395 to 975 C, the closest chemical compounds to zirconium are Zr5Al3, Zr2Al and ZrsAl. At a temperature of 1350 C, 95% aluminum dissolves in p-zirconium. In total, there are nine chemical compounds in this system. Below 980 C, the p-solid solution decomposes into two solid solutions rich in zirconium and niobium, respectively. As the temperature decreases, the region of separation in the solid state expands up to a monotectoid temperature of 610 C.
The left side of the dual C-A1 state diagram is shown in FIG.
Scheme of changing the content of the low-melting component in a brazed joint made of metal A during diffusion soldering. Diffusion brazing of titanium and its alloys with solders rich in copper, silver, and nickel is promising. Judging by the data in Table. 30 and double phase diagrams, the widest regions of solid solutions in these alloys are in the temperature range of the existence of p-solid solutions. Silver is fairly low-melting, while copper and nickel form relatively low-melting eutectics with titanium. Intermetallics formed in brazed joints of titanium joints made with solders containing these metals are also relatively fusible.
But this similarity is only superficial. In reality, there is a fundamental difference between the vertical cuts of a ternary system and a double state diagram.
The position of the vertical cuts. in the state diagram.| Vertical section diagram I. | Vertical section diagram. Section in fig. 90, which looks like a double state diagram, differs significantly from it in this sense.
The scientific basis of steel heat treatment technology is the joint analysis and application of state diagrams (phase diagrams) and diagrams of the decomposition of supercooled austenite. By now, iron-based alloys are known to have double state diagrams; and for the majority of alloys and steels widely used in industry - and triple diagrams.
A variant of the state diagram of a system with a melting ternary chemical compound incogruent in the case when one of the cuts from the compound to the components is not double.| CS vertical section diagram. On fig. 476 shows a vertical section of the state diagram along the AS line. Consequently, beyond the point p, the cut AS loses the properties of the double state diagram. The dotted lines show the multi-stable parts of the liquidus and solidus of the 8-solid solution with a common hidden maximum.
Diagram of a vertical section along the line VC.| Isothermal section of the phase diagram at the temperature corresponding to the eutectic point e5 in the VC binary system.
From what has been said, it follows that the vertical section of the state diagram along the line VC (Fig. 439) has the properties of a double state diagram, since the lines V e & and C e of the liquidus are conjugated with the lines V d9 and C c3 of the solidus.
Naturally, the question arises about the origin of this graphite. It has already been pointed out above (§ 44) that there are two theories to explain the origin of graphite, based either on a double state diagram or on a single one.
Isothermal sections below the eutectic point c5.| Isothermal at a temperature corresponding to the triple eutectic point E. Due to these properties of the vertical section VC, it and similar sections are called quasi-binaries, sometimes also pseudobinaries, indicating their similarity with the diagrams of binary systems. They should, however, be called simply double cuts, since the prefix quasi means allegedly, as if, and the prefix pseudo means false, false, which casts doubt on the similarity of UTIKh cuts with double state diagrams, rather than emphasizes it.
Practical applications in mechanical engineering are copper-tin alloys containing up to 12% Sn. The left side of the double copper-tin state diagram is shown in Fig.
The formation of solid solutions leads to a change in the transformation temperatures. To assess the effect of alloying elements on titanium, it is important to establish how they affect the polymorphic transformation of titanium and whether they form chemical compounds with titanium. The answer to these questions is provided by the dual state diagrams shown in Fig. 356 as a classification scheme.
For ternary systems, the phase rule is written as / 4 - p; compared to binary systems, one additional degree of freedom appears. Three-phase ternary alloys have one degree of freedom; these alloys occupy corresponding volumes in the spatial state diagram. As in the case of two-phase regions on double phase diagrams, the temperature of a three-phase ternary alloy can be changed, but in this case, at each given temperature, the compositions of all three equilibrium phases turn out to be quite definite. In two-phase volumes of the spatial state diagram of a ternary system, the temperature and composition can be changed independently of each other. In a single-phase volume, the number of degrees of freedom of the ternary alloy reaches a maximum value of three: here you can change the temperature, as well as the concentrations of two of the three components. Since the concentrations of all three components are equal to 100% in total, only two concentrations can be changed independently of each other, since the content of the third component is determined by the difference between 100% and the sum of the concentrations of the other two components.
Vertical section. The favorable effect of molybdenum is explained by the fact that in its presence the formation of the chemical compound TiCra is hindered. The maximum solubility of chromium in a-titanium, in accordance with the double state diagram of Ti-Cr, is 0 5% wt.
This book is a textbook on the heat treatment of metals for engineering colleges. To study heat treatment in this book, the student is required to know the basics of metal science in the volume of the book by A. I. Samokhotsky and M. P. Kunyavsky Metal Science or the book by M. S. Aronovich and Yu. books by B. S. Natapov Metal Science, which are also textbooks for technical schools. It is assumed that the student is well acquainted with the main types of double state diagrams, with the crystalline structure of metals and alloys, with the elementary structures of steels and cast irons, with the methodology of metallographic research and with mechanical tests. These questions are not addressed in this book at all. In the first chapter, briefly, but in more detail than in the mentioned textbooks on metallurgy, the classification and characteristics of steels and the state diagram of iron-carbon alloys are considered.
State diagram with a continuous series of solid solutions with a maximum point on the liquidus and solidus surfaces.| Projection of the state diagram shown in 69 onto the concentration triangle. In this sense, isothermal sections are no different from a double state diagram. However, the essential difference between them is that the double diagram makes it possible to judge equilibria. The fundamental difference between isothermal and vertical cuts is clear from the above.
Typically, vertical sections are built on the composition lines of ternary alloys, which contain a constant amount of one of the components. A, which exceeds the content of this component in the ternary eutectic and in the double eutectics e and e3, is shown in FIG. The lower part of this section outwardly resembles a double diagram of state of the eutectic type, if you do not pay attention to the designations of different phase regions.
Let us pay attention to the fact that the straight line SG in Fig. 470 passes through the lines ee, d d, EZE1 of the three-phase equilibrium x Y - b 8 between the liquid and solid solutions of the C component and the Yr compound. The lines of intersection with these surfaces (Fig. 472) are not elements of the double state diagram CVlt, therefore, beyond the point p, the cut loses the properties of the double state diagram.
Edited by L. N. Komissarova and V. I. Spitsyn. - M.: Publishing house of foreign literature, 1963. - 345 p.
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") The state diagram of the Zr02-La203 system was studied in sufficient detail by the methods of thermal, dilatometric, X-ray and phase chemical analyzes using precision instruments. In addition, electrical conductivity was measured and a petrographic study was carried out. Based on these studies, a detailed picture of phase transformations in the Zr02 system was presented - La203, the formation of a stable crystalline compound La»Zr207 with the cubic structure of pyrochlore and a number of solid solutions based on tetragonal and monoclinic Zr02; chemical compound La2Zr207 and hexagonal La203 was found.
Compounds of the composition Me2Zr207 were also obtained by heating Zr02 with oxides of cerium (3-f), neodymium, samarium and gadolinium above 1200 ° .- Note. ed.
154
Chapter J. Zirconium Oxides and Zirconates
Fluorosilicates also react with zirconium dioxide to form fluorozirconates (see Fluorine section). As a result of heating zirconium dioxide with oxides of elements of this group, the following compounds are formed: 1) GeO2-ZrO2 with a tetragonal lattice (a = 4.871; c = 10.570 A); 2) cPbZrO3 with a pseudotetragonal lattice at 20° (a=4.152, c - = 4.101 A), turning into a cubic one at 230° and 3) Zr02Si02. For a detailed description of this last connection, see Chap. 5. No connection with Zr02 was obtained for tin oxide. Gold. See copper.
Hydrogen. Zirconium dioxide does not interact with hydrogen, and no interaction was observed even at a temperature of 2000° and a pressure of 150 atm. Calcium hydride reduces zirconia to metal. Hydrogen fluoride and hydrofluoric acid, when interacting with zirconium dioxide, form zirconium fluoride compounds; hydrochloric acid dissolves zirconium dioxide if its particles are small enough or in the appropriate energy state. Water does not form compounds with zirconium dioxide.
Indium. See aluminum.
Iodine. See bromine.
Iridium, cmium, palladium, platinum, rhodium and ruthenium. Information on the interaction of these elements or their compounds with zirconium dioxide is not available in the literature.
Iron. See cobalt.
Lanthanum and lanthanides. See cerium.
Lead. See germanium.
Magnesium. See cadmium.
manganese and rhenium. The reactions of these elements or their compounds with zirconium dioxide are not known. For a mixture of Zr02 and Mn304, the eutectic temperature is 1620 .
Mercury. See cadmium.
Molybdenum and tungsten. According to the work, tungsten should react with zirconia at very high temperatures, forming an alloy of tungsten with zirconium. There are no other data on the interaction of zirconium dioxide with molybdenum and tungsten or their compounds1).
Nickel. See cobalt.
Niobium, phosphorus, tantalum and vanadium. Information on the interaction of these elements or their compounds with zirconium dioxide is absent in the literature, except for the reaction with phosphorus pentachloride, which results in the formation of zirconium tetrachloride [152]2).
Nitrogen. Nitrogen and its compounds do not react with zirconium dioxide, with the exception of ammonium bifluoride, which in this case forms ammonium fluorozirconates.
Osmium. See iridium.
") Zirconium dioxide can interact with tungsten trioxide above 1000 °, and the compound ZrOW04 is formed. Zirconyl tungstate has some volatility in a stream of water vapor, moderately dissolves in NaOH and Na2F2 when heated, slightly interacts with concentrated solutions of H2SO4, HC1 and NH4OH ., - Note ed.
2) Zirconium dioxide can interact with oxides of niobium and tantalum at temperatures of 1300° and above. The process is accompanied by the formation of compounds of niobate and zirconyl taitalate, the composition of which corresponds to the formula ZrOR207. Both compounds are thermally stable and melt at 1700 + 20° and 1730 ± 20°, respectively. They have increased resistance to various chemicals: acids, alkalis and chlorinating agents. Zirconyl tantalate is more stable than isobate. It is insoluble in hot solutions of concentrated HC1 and H2SO4 in a mixture of ammonium sulfate with sulfuric acid and does not fuse with sodium pyrosulfate, K2CO3 and barium peroxide.- Approx. ed.
3. Zirconium dioxide
155
Oxygen. Oxygen does not chemically interact with zirconium dioxide. The reactions of zirconia with various oxides are described in the respective sections.
Palladium. See iridium.
Platinum. See iridium.
Potassium. See cesium.
Rhenium. See manganese.
Rhodium. See iridium.
Ruthenium. See iridium.
scandium and yttrium. Information on the interaction of these elements or their compounds with zirconium is absent in the literature. It is only known that yttrium oxide Y203 with its content from 7 to 55 and from 76 to 100 mol. % forms with zirconium dioxide at 2000° solid solutions of cubic structure 1).
The state diagram of copper - aluminum is built in the entire range of concentrations by the methods of thermal, metallographic, X-ray analysis and is a complex diagram with intermediate phases. The state diagram of copper - aluminum (Fig. 1) is based on the work performed by various authors over a long period of time. The region of solid solutions based on copper (α-phase) extends up to 9% (by mass) Al. With decreasing temperature, the solubility of aluminum in copper also increases at temperatures of 1037; 900; 800; 700; 500 °C is 7.4; 7.8; 8.2; 8.8; 9.4% (by weight) Al, respectively. Phase a has an fcc lattice similar to that of pure copper, the period of which increases with increasing aluminum content and in an alloy with 10.5% (by weight) Al is 0.3657 nm.
The β phase is a solid solution based on the Cu 3 Al compound. In β-region alloys, depending on heat treatment and cooling conditions, two metastable intermediate phases can be observed: β" and β.
Phase γ 1 -solid solution based on the compound Cu 3 Al 4 exists in the concentration range of 16.0...18.8% (by mass) Al and has a monoclinic lattice with 102 atoms in the unit cell. The α 2 phase has a lattice similar to that of the α phase.
In the region up to 20% (by mass) Al, the liquidus of alloys consists of four branches of primary crystallization of phases α, β, χ and χ 1 . At 1037 C, the α + β eutectic crystallizes with the eutectic point at 8.5% (by weight) Al. At temperatures of 1036 and 1022 °C, the peritectic reactions Zh + β ↔χ and Zh + χ↔γ 1 proceed. respectively. Phase χ exists in the temperature range 1036...936 °C. Phase β crystallizes from the melt along a curve with a maximum at a temperature of 1048°C and corresponds to a concentration of 12.4% (by mass) Al. In the solid state, there are a number of eutectoid and peritectoid transformations in this region. At 963 °С, the χ phase decomposes into β- and γ 1 -phases. The eutectoid point corresponds to 15.4% (by weight) Al. At 780 °C, the γ 1 phase decomposes by eutectoid reaction into β and γ 2 phases. At 873 °C, the γ-phase is formed by the peritectonic reaction. It is assumed that in the γ 2 -phase a phase transformation occurs in the temperature range of 400...700 °C with an aluminum content at the eutectoid point of 11.8...11.9% (by weight). In the concentration range of 9...16% (by mass) of Al, the existence of another stable phase, χ or α 2 , is assumed, which is formed by the eutectoid reaction at 363 ° C and the aluminum content at the eutectoid point is ∼11.2% (by mass). The concentration limits of the homogeneity region of this phase have not been established.
Based on literature data on the thermodynamic properties of components and intermediate phases, as well as on the basis of experimental data on phase equilibria, the authors calculated the phase diagram of the Cu-Al system. The values of the calculated temperatures of phase transformations practically coincide with the data of the work.
Copper - beryllium
The state diagram of copper - beryllium has been studied by many researchers. It is built over the entire range of concentrations (Fig. 2). The crystallization curves of the alloys consist of four branches corresponding to the crystallization of the α, β, δ, and β-Be phases. The β phase crystallizes along a curve with a minimum at 860°C and 5.3% (by mass) Be. At 870°C, the β-phase is formed by the peritectic reaction, and at 578°C, the β-phase decomposes by the eutectoid reaction. There is evidence of a higher eutectoid transformation temperature of 605°C.
The solubility of beryllium in copper at the eutectoid transformation temperature is 1.4% (by weight). With decreasing temperature, the solubility of beryllium decreases and is: at 500 ° C - 1.0% (by mass), at 400 ° C - 0.4% (by mass), at 300 ° C - 0.2% (by mass) . In the concentration range of 50.8 ... 64.3% (at.) Be at 930 ° C, the peritectic reaction of the formation of the β "-phase occurs, and at 1090 ° C, the eutectoid transformation β ↔α-Be + δ takes place. Phase boundaries regions δ/δ + α-Be and δ + α-Be/α-Be pass at 1000 °C through 81.5 and 92.5% (at.) Be, at 900 °C - 81.0 and 93.0 % (at.) Be, at 700 °C - 80.8 and 95.5% (at.) Be, respectively.
The δ phase is formed by a peritectic reaction at a temperature of 1239°C. The copper-based solid solution (α-phase) has an fcc lattice with a period of α = 0.3638 nm at 2.1% (by mass) Be, the δ-phase has a disordered bcc lattice with a period of α = 0.279 nm at 7.2% (by mass) Be, β'-phase has an ordered body-centered cubic lattice of the CsCl type with a period of α = 0.269 ... 0.270 nm, the δ-phase has a cubic lattice of the MgCu 2 type with a period of α = 0.5952 nm. The β-Be phase is high-temperature, and α-Be is a low-temperature modification of a solid solution based on beryllium.
According to , where part of the diagram is shown up to 50% (at.) Cu, the δ-phase (Be 4 Cu-Be 2 Cu) melts congruently at 1219 ° C and 22% (at.) Cu. The β-phase has a structure of the MgCu 2 type and changes the lattice period in the homogeneity region from α = 5957 nm to α = 0.5977 nm at 25% (at.) Cu.
Copper - iron
The copper-iron state diagram has been studied by many researchers. The results of these studies are analyzed in detail in the works. The main contradictions relate to the question of the complete or partial miscibility of copper and iron in the liquid state. As a result of the experiments, it was found that there is no stratification in the copper-iron system, however, for the supercooled state (100 °C), stratification takes place. The separation region is almost symmetrical to the axis corresponding to the equiatomic composition, and the critical mixing temperature lies 20 °C below the liquidus temperature at the equiatomic composition.
On fig. Figure 3 shows the state diagram of copper-iron according to the data. Two peritectic and one eutectoid transformations have been established at temperatures of 1480; 1094 and 850 °C. Solubility of iron in copper at 1025; 900; 800 and 700 °C is 2.5; 1.5; 0.9; 0.5% (by mass) Fe, respectively. The lattice period of the copper-based solid solution for an alloy with 2.39% (at.) Fe is 0.3609 nm. The lattice period of α-Fe (bcc) increases from 0.28662 ± 0.00002 to 0.28682 nm with the addition of 0.38% (at.) Cu.
Copper - cobalt
The state diagram of the copper-cobalt system is shown in fig. four . It agrees well with the results of earlier studies of this diagram. In this system, as a result of supercooling by 100 °C or more, a region of immiscibility in the liquid state appears, which is almost symmetrical with respect to the axis corresponding to the equiatomic composition. With this composition, the critical mixing temperature lies 90 °C below the liquidus curve.
The Cu-Co system is of the peritectic type. The temperature of the peritectic reaction is 1112 °C. Data on the solubility of cobalt in a solid solution based on copper (β) and copper in a solid solution based on cobalt (a) in the temperature range of 900 ... 1100 ° C are given in Table. one.
Copper - silicon
The state diagram of copper - silicon is shown in fig. 5 (according to the totality of works). The system contains an α-solid solution based on copper, β-, δ-, η-phases, as well as K-, γ-, and ε-phases formed by peritectoid reactions.
The region of existence of the β-phase [bcc lattice with α = 0.2854 nm at 14.9% (at.) Si] is in the temperature range 852...785 °C; it is formed by a peritectic reaction with a peritectic transformation point of 6.8% (by mass) Si. The region of existence of the β-phase covers the temperature range 824...710 °C and is formed by the peritectic reaction; peritectic transformation point 8.65% (by mass) Si. The η phase has two modifications: η′ and η″. In the temperature range of 620...558 °C, the η↔η′ transformation takes place, and in the range of 570...467 °C, the η′↔η″ transformation takes place. The lattice of the η-phase is similar to that of γ-brass.
The K phase is formed by the peritectoid reaction at +842°C and exists up to 552°C; the peritectoid point corresponds to 5.9% (by mass) Si. The K-phase has a close-packed hexagonal lattice with α = 0.25543 nm and c = 0.41762 nm at 11.8% (at.) Si and α = 0.25563 nm and c = 0.41741 nm at 14.6% (at.) Si. The γ phase is formed by a peritectoid reaction at 729°C and is stable up to room temperature; the peritectoid point corresponds to 8.35% (by mass) Si.
The γ phase has a cubic lattice of the β-Mn type with a period α = 0.621 nm.
The ε phase is also formed by the peritectoid reaction at 800°C and exists in a narrow concentration range of 10.6...10.7% (by mass) Si, and is stable up to room temperature. It has a bcc lattice with α = 0.9694 nm. The solubility of copper in silicon is negligible and amounts to 2.810 -3; 2 10 -3; 5.5 10 -4 ; 8.5 10 -5 ; 5.3 10 -6% (at.) at temperatures of 1300; 1200; 1000; 800 and 500 °C, respectively. The solubility of silicon in copper is significant and amounts to ∼5.3% (by weight) at 842°C.
Copper - manganese
The diagram of the state of the system copper - manganese is built in the entire range of concentrations. Here it is given according to the data (Fig. 6). Copper and manganese form a minimum on the liquidus curve at a content of ∼37% (at.) Mn and a temperature of 870 ± 5 °C. Transformations in the solid state are associated with ordering processes in alloys on the copper side and allotropic modifications of manganese. The solid solution (α-Cu, γ-Mn) is ordered at ∼16% (at.) Mn (MnCu 5) and 400 °C and at ∼25% (at.) Mn (MnCu 3) and 450 °C.
The solubility of copper in α-Mn and β-Mn phases is negligible. The system undergoes a continuous transition from the face-centered cubic lattice of a copper-based solid solution (α-Cu) to the face-centered tetragonal lattice of γ-Mn.
Copper - Nickel
The state diagram of the copper-nickel system is a system with a continuous series of solid solutions. Figure 7 shows the results of experimental studies that are in good agreement with each other. In the solid state, there are transformations associated with magnetic transformations in nickel. All alloys of the Cu-Ni system have an fcc lattice. Assumptions about the existence of CuNi and CuNi 3 compounds in the system were not confirmed in later works. The alloys of this system are the basis of industrial alloys of the cupronickel type.
Copper - tin
On fig. 8 is a state diagram built on the basis of a large number of works. The existence of a number of phases was established in the system, which are formed both during primary crystallization and during transformation in the solid state. Phases α, β, γ, ε, η are formed during primary crystallization, phases ζ and δ - in the solid state. Phases β, γ, and η are formed by peritectic reactions at temperatures of 798, 755, and 415°C. The lattice period of the α-phase increases from 0.3672 to 0.3707 nm. The β and γ phases are crystallographically similar and have a bcc lattice.
The ε phase exists on the basis of the Cu 3 Sn compound and has a rhombic lattice. The η phase corresponds to the Cu 6 Sn 5 compound. It is ordered at 189...186 °C. The ζ phase has a hexagonal lattice with the expected composition Cu 20 Sn 6 . The δ-phase has the structure of γ-brass, it is an electronic compound and corresponds to the formula Cu 31 Sn 8 at 20.6% (at.) Sn.
The solubility of tin in copper, according to X-ray spectral analysis, is, % (at.) Sn [% (by mass) - in parentheses]: 6.7 (11.9); 6.5 (11.4); 5.7 (10.10) at temperatures of 350; 250; 150 °C, respectively. The solubility of copper in tin in the solid state at the eutectic temperature is 0.01% (at.) (according to Tokseitov et al.).
Copper - lead
The state diagram of copper - lead, built in the entire range of concentrations, is shown in fig. 9 according to work. The state diagram of the copper-lead system is characterized by the presence of monotectic and eutectic transformations. The temperature of the monotectic transformation is (955 ± 0.5) C, and the length of the region of immiscibility at this temperature is 15.7-63.8% (at.) Pb. The eutectic point corresponds to 0.18% (at.) Pb, and according to the data - a temperature of 326 ° C and 0.2% (at.) Pb. The solubility curve between the monotectic temperature and the melting point of lead is fairly well defined. It is established that this curve intersects the monotectic horizontal at a lead content of 67% (at.). The solubility of lead in copper in the solid state at temperatures above 600 ° C is not more than 0.09% (at.). The solubility of copper in solid lead is less than 0.007% (by mass).
Copper - antimony
The state diagram of copper - antimony is presented according to the data in fig. ten.
In the alloys of this system, a high-temperature β-phase with an fcc lattice of the BiF 3 type was found, which melts congruently at 684 °C and the content of Sb in the alloy is 28.6% (at.). At 435°C, the β-phase decomposes eutectoidally into the phase k and Cu 2 Sb. The eutectoid point corresponds to 24% (at.) Sb. The maximum solubility of the β-phase is 20...32%) (at.) Sb. Other intermediate phases - η, ε, ε' and k - are formed by peritectoid reactions at temperatures of 488 °C (η), 462 °C (e). ε'-phase has a hexagonal lattice with periods α = 0.992 nm, c=0.432 nm and exists in the temperature range ∼375...260 °C. the c-phase has a rhombic structure of the Cu 3 Ti type, exists in the range of 450 ... 375 ° C and decomposes into the ε-phase and Cu 2 Sb at a temperature of 375 ° C or the ε'-phase and Cu 2 Sb (according to other authors ). The η phase has a homogeneity range from 15.4 to 15.8% (at.) Sb at 426°C. The intermediate phase Cu 2 Sb is formed by the peritectic reaction at 586 °C and has a narrow homogeneity range of 32.5...33.4% (at.) Sb. It has a tetragonal lattice. The maximum solubility of antimony in copper in the solid state at temperatures of 600; 550: 500; 450; 400; 360; 340 and 250 °C is 5.79; 5.74; 5.69; 5.44; 4.61; 3.43; 3.02; 1.35% (at.) or 10.53; 10.44; 10.37; 9.92; 8.48; 6.38; 5.64; 2.56% (by weight) respectively.
Copper - phosphorus
The state diagram of the copper-phosphorus system is shown according to the data in fig. 11. According to the results of later work, two compounds were found in the system: Cu 3 P and CuP 2. The temperature of formation of the Cu 3 P compound directly from the melt is given by various authors in different ways: 1005; 1018 or 1023; 1022 °C. The area of homogeneity of the Cu 3 P compound is 31% (at.) P at the eutectic temperature and 27.5% (at.) P at 700 °C. The Cu 3 P compound has a hexagonal lattice with parameters α = 0.695 nm, c = 0.712±0.02 nm, c/α=1.02.
The CuP 2 compound crystallizes directly from the melt at 891°C. A eutectic reaction occurs between the Cu 3 P compound and copper at 714 ° C, the eutectic point corresponds to 15.72% (at.) P.
Between compounds Cu 3 P and CuP 2 there is a eutectic equilibrium at 833 °C. Composition of the eutectic point 49% (at.) R.
In the region of the diagram between phosphorus and the CuP 2 compound, the existence of a degenerate eutectic at 590 °C is assumed.
The solubility of phosphorus in copper is given in table. 2.
(Note. In parentheses is the phosphorus content in percent by weight.)
Copper - chrome
The copper-chromium state diagram has been most extensively studied in the copper-rich region. It is presented in full in the work of G.M. Kuznetsova and others according to thermodynamic calculation data and data on the interaction parameters of the components (Fig. 12). There are two phases in the alloy structure: solid solutions based on copper (α) and chromium (β). At 1074.8 ° C, a eutectic transformation occurs at a chromium content of 1.56% (at.). The solubility of chromium in copper according to different authors is given in table. 3.
The solubility of copper in chromium in the solid state varies from 0.16% (at.) at 1300°C to 0.085% (at.) at 1150°C.
Copper - zinc
In copper alloys, the greatest practical interest among the elements of group II of the periodic system D.I. Mendeleev represents zinc. The state diagram of copper - zinc has been studied by many researchers in the entire range of concentrations. On fig. Figure 13 shows a state diagram built on the basis of a set of works in which the methods of thermal, X-ray, metallographic, electron microscopic analyzes, and determination of the liquidus temperature were used.
The liquidus line of the copper-zinc system consists of six branches of primary crystallization of phases α, β, γ, δ, ε and η. There are five peritectic transformations in the system, % (at.):
1) W (36.8 Zn) + α (31.9 Zn) ↔ β (36.1 Zn) at 902 °C;
2) W (59.1 Zn) + β (56.5 Zn) ↔ γ (59.1 Zn) at 834 °C;
3) W (79.55 Zn) + γ (69.2 Zn) ↔ δ (72.4 Zn) at 700 °C;
4) L (88 Zn) + δ (76 Zn) ↔ ε (78 Zn) at 597 °C;
5) W (98.37 Zn) + ε (87.5 Zn) ↔ η (97.3 Zn) at 423 °C.
The solubility of zinc in a copper-based solid solution first increases from 31.9% (at.) at 902°C to 38.3% (at.) at 454°C, then decreases and amounts to 34.5% (at.) at 150 °С and 29% (at.) at 0 °С.
In the region of existence of the α-phase, two modifications α 1 and α 2 are defined. The region of existence of the β phase is in the range from 36.1% (at.) Zn at 902 °C to 56.5% (at.) Zn at 834 °C and from 44.8% (at.) Zn at 454 °C up to 48.2% (at.) Zn at 468 ° C. In the temperature range of 454 ... 468 ° C, a transformation or ordering occurs.
The β' phase decomposes according to the eutectoid reaction β'↔α + γ at a temperature of ~255°C. β-phase exists in four modifications: γ'''-phase up to temperatures of 250...280 C, above 280°C γ'-phase is stable, which at 550...650°C passes into γ'-phase; above 700°C there is a γ phase. The δ phase exists in the range of 700...558 °C, decomposing eutectoidally according to the reaction δ↔γ + ε at 558°C.
The solubility of copper in a zinc-based η-solid solution decreases from 2.8% (at.) at 424°C to 0.31% (at.) at 100°C. The lattice periods of the α-solid solution based on copper increase with increasing zinc concentration.
The β phase has a body-centered cubic lattice of the W type, the β'-phase has an ordered body-centered lattice of the CsCl type. The lattice period of the β'-phase increases from 0.2956 to 0.2958 nm in the concentration range of 48.23...49.3% (at.) Zn.
The γ phase has a γ-brass type structure. Its composition corresponds to the stoichiometric composition of Cu 5 Zn 8 . The γ″'-phase has a rhombic lattice with periods α = 0.512 nm, b = 0.3658 nm, and c = 0.529 nm.
The γ″ phase has a cubic lattice with a period α = 0.889 nm. The structure and lattice parameters of the γ' and γ phases have not been determined. Phase 3 has a bcc lattice with a period α = 0.300 nm at 600°C for an alloy with 74.5% (at.) Zn. The ε phase has a hexagonal lattice of the Mg type.
Alloys based on the copper-zinc (brass) system are widely used in various industries: they are characterized by high manufacturability and corrosion resistance. The manufacture of various parts and castings from alloys of this system is not particularly difficult. Alloys of grades L96, L90, L85, L80, L75, L70, L68, L66, L63, L59 - simple brass - are processed by pressure in cold and hot state and have a single-phase structure, which is a solid solution based on copper (a) for alloys with copper content of at least 61% (by mass) and two-phase (α + β) for L59 alloy. Single- and two-phase alloys (α, α + β, β) alloyed with aluminum, iron, manganese, silicon, tin, lead are used to obtain castings by various methods.
With the development of new branches of science and technology, the requirements for the properties of aluminum alloys are also expanding. This leads, as a rule, to complications of their composition. Increasingly, additives of such refractory elements as zirconium, manganese, chromium, titanium, vanadium, boron and others are used as alloying components.
The works of M.V.Maltsev, V.I.Dobatkin, A.Kibula and other authors showed that the latter, when introduced into the melt, contribute to the refinement of the grain of ingots, eliminate structural heterogeneity, significantly improve the casting and mechanical properties of alloys, and provide large-sized forgings and stampings , as well as other semi-finished products manufactured with a small degree of deformation from alloys D16, ACM, 1911.1915. For such casting alloys as VAL-1, VAL-5, AL4M and others, the expediency of using refractory alloying components is also shown.
Zirconium is widely used for alloying aluminum alloys, which, like other transition metals, has a pronounced modifying effect.
The state diagram of the Al-Zr system belongs to the peritectic type. As the diagram in Fig. 1.1 shows, a peritectic reaction occurs between the liquid (0.11% zirconium) on the side of pure aluminum and the ZrAl 3 compound with the formation of a solid solution of aluminum (0.28% zirconium). The reaction temperature is 660.5 °C.
The paper points out that the study of double state diagrams characterizing the interaction between aluminum and alloying components makes it possible to judge the effectiveness of one or another element as a modifier. The most effective modifiers are those metals that form state diagrams of the peritectic or eutectic type with aluminum with refractory compounds, the liquidus of which is largely shifted towards aluminum. An example of such a diagram is the Al-Zr diagram.
In addition to the ability to grind grain, zirconium can significantly affect the recrystallization temperature of aluminum alloys. The last action is associated with the formation and decay of solid supersaturated solutions of zirconium in aluminum. In the finished product, as a rule, there are no supersaturated solid solutions. In the process of the technological cycle of production of semi-finished products, associated with numerous heatings of the alloy, alternating with deformations, these solid solutions disintegrate with the release of secondary aluminides. The degree of decomposition of the solid solution, dispersion and the nature of the distribution of decomposition products, ultimately determine the effect of transition metals on the mechanical properties of deformed semi-finished products.
Elagin in his work, considering the effect of transition metals on the recrystallization temperature, indicates that the greatest effect on the recrystallization temperature is exerted by dispersed intermetallics - decomposition products of solid solutions. To a lesser extent, the recrystallization temperature is increased by non-decomposed solid solutions. And the coagulation of the decomposition products of solid solutions leads to the opposite effect. Solid solutions of various transition metals differ in their stability. The most stable is a solid solution of zirconium and aluminum. In the main volume of this solution, decomposition proceeds very slowly. Also, the coagulation of decomposition products is slower compared to other comparable alloys.
Thus, the work notes an increase in the fluidity of Al-Mg alloys. In the AL27-1 alloy, zirconium additions reduce the tendency to cracking and reduce the hydrogen content.
According to Kozlovskaya, the replacement of part of the manganese in the D16 alloy with zirconium contributes to a strongly pronounced press effect, the absence of a coarse-grained rim, and an increase in ductility in the transverse direction.
In alloys of the Al-Zr-Mg system, zirconium additives significantly reduce stress corrosion, and also increase the corrosion resistance of aluminum alloys in aggressive environments.
The far from complete information given on the role of zirconium in aluminum alloys indicates that zirconium is increasingly being used as an alloying element.
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