Phase Diagrams Of Alloys Research Articles

Isothermal Phase Diagrams of Binary Alloys and Two Oxidants

An example of an isothermal thermodynamic phase diagram of a quaternary system composed of a binary alloy and two oxidants has been calculated under appropriate values of the stability of the corresponding compounds, assuming that each metal forms only one compound with each oxidant. Initially, two-dimensional sections of the complete three-dimensional diagram made along planes corresponding to constant values of one of the variables involved were examined in detail. The actual structure of this type of three-dimensional diagram was then discussed by analyzing the shape and the boundaries of the various regions corresponding to the conditions of stability of each phase taken separately or in combination with other phases.

Phosphorus Particle Composite Plating with Ni–P Alloy Matrix

Ni–P alloy films containing phosphorus particles (called “Ni–P alloy composite films”) were fabricated by electrodeposition and were subsequently subjected to heat-treatment. Their compositions and microstructures were characterized, and their friction properties were evaluated using a ball-on-plate method. Composite electroplating in the nickel sulfate and chloride bath containing phosphorus acid and micrometer-sized phosphorus particles resulted in the Ni–P alloy coating with enhanced deposit phosphorus content. The phosphorus content of the films increased with increasing phosphorus particle concentration in the composite plating baths, reaching a maximum value of 29.0 atom %. The phosphorus particles were homogeneously distributed in this Ni–29.0 atom % P alloy composite film. Heat-treatment converted the phases of the alloy composite films from an amorphous phase to stable crystalline phases, which are the same as those in the Ni–P binary alloy phase diagram. The friction coefficients of the Ni–P alloy films increased with increasing cycle number, whereas those of the Ni–P alloy composite films remained relatively constant. The alloy composite films had lower friction coefficients than the Ni–P alloy films both before and after heat-treatment. These results indicate that phosphorus particles are beneficial for maintaining a lower and stable friction coefficient during the ball-on-plate reciprocating friction test.

Assessing Aptitude of Plated Ni–W Film as Mold Materials for Borosilicate Glass

We propose the Ni–W plating film as a mold material for the hot embossing of borosilicate glass. The lifetime of a Ni–W plating mold is important from a practical perspective. However, there have been no previous reports on the life of a mold. Contact angle has been reported as a parameter for the comparative assessment of wettability. In this report, we identified the components of borosilicate glass reacted with a Ni–W film by elemental analysis together with a wettability test. In the wettability test, increasing temperature caused a decrease in of contact angle, which is caused by the chemical reaction at the center of glass. In the results of the elemental analysis of the Ni–W film in contact with glass, Zn, a constituent of the glass, was not detected in the noncontact zone, but was detected in the contact zone. There is no binary alloy phase diagram of W–Zn. It is considered that W does not form an alloy with Zn. Results from the reaction of Zn on Ni indicated an increase in the wettability of borosilicate glass for the Ni–W plating film.

Ternary Iron Phase Diagram Updates

This addendum is intended to provide updates on phase diagrams of ternary iron al-loys, which were published as a series of monographs by the cooperating societies: ASM International, Indian Institute of Metals, and the Institute of Materials (Lon-don). Updates on 14 systems reviewed in Part 1 of the series were published inJ Phase Equilibria, 14(5), 6145-633 (1992). This issue contains updates on 12 sys-tems from among those reviewed by Raynor and Rivlin, which was published as part 4 of the Series by the Institute of Materials (London) in 1988. The second and third installments of the updates from Part 4 will follow in the future issues of this journal.

Influence of global magnetic state on chemical interactions in high-pressure high-temperature synthesis of B2 Fe2Si

We show that effective chemical interactions in an alloy can be tuned by its global magnetic state, which opens exciting possibilities for materials synthesis. Using first-principles theory we demonstrate that at pressure of 20 GPa and at high temperatures, the effective chemical interactions in paramagnetic Fe–Si system are strongly influenced by the magnetic disorder favoring a formation of cubic Fe2Si phase with B2 structure, which is not present in the alloy phase diagram. Our experiments confirm theoretical predictions, and the B2 Fe2Si alloy is synthesized from Fe–Si mixture using multianvil press.

Study on the Solidus Line in Sn-Rich Region of Sn-In Phase Diagram

Binary phase diagrams are important tools for designing desired alloys. In the Sn-rich region of the Sn-In alloy phase diagram, the solidus line appears as a dotted line in current literature plots to indicate uncertainty. The contour of the solidus has now been clarified as a result of the present investigation. Four alloys, Sn70In30, Sn75In25, Sn80In20, and Sn85In15 were melted at 300 °C for 10 h and annealed between 120 and 200 °C in the (L + γ) two-phase region. The morphology and chemical compositions of annealed specimens were analyzed using both field emission scanning electron spectroscopy and energy-dispersive x-ray spectrometry. The results reveal that the liquid phase, initially appearing at the eutectic temperature, invades the solid along grain boundaries with penetration gradually increasing with increasing annealing temperature and a granular structure form. The average compositions in grains of Sn70In30, Sn75In25, Sn80In20, and Sn85In15 specimens correspond to the solidus concentrations, and the solidus line and (β + γ)/γ phase boundary can be determined as a fit to these temperature-composition points.

Capability of focused Ar ion beam sputtering for combinatorial synthesis of metal films

The authors examined the use of focused Ar ion beam sputtering (FAIS) for combinatorial synthesis. A Langmuir probe revealed that the electron temperature and density for FAIS of metal film deposition was lower than that of other major combinatorial thin film growth techniques such as pulsed laser deposition. Combining FAIS with the combinatorial method allowed the compositional fraction of the Pt–Ru binary alloy to be systematically controlled. Pt–Ru alloy metal film grew epitaxially on ZnO substrates, and crystal structures changed from the Pt phase (cubic structure) to the Ru phase (hexagonal structure) in the Pt–Ru alloy phase diagram. The alloy film has a smooth surface, with the Ru phase, in particular, showing a clear step-and-terrace structure. The combination of FAIS and the combinatorial method has major potential for the fabrication of high quality composition-spread metal film.

Observation of de Haas-van Alphen oscillations across the phase diagram of CeRh1-xCoxIn5

The evolution of the Fermi surface of CeRh1-xCoxIn5 was studied as a function of Co concentration x via measurements of the de Haas-van Alphen effect. We observe several quantum oscillation frequencies in single crystal samples prepared with values of x spanning the alloy phase diagram. By tracking the evolution of these frequencies as the applied magnetic field is rotated, we establish that the Fermi surface undergoes an abrupt change in shape when x ≊ 0.4. This is well away from the quantum critical concentration x ≊ 0.8 where antiferromagnetic order gives way to paramagnetism.

User applications of alloy phase diagrams

User applications of alloy phase diagrams

Fe–Ni many-body potential for metallurgical applications

A many-body interatomic potential for the Fe–Ni system is fitted, capable of describing both the ferritic and austenitic phase. The Fe–Ni system exhibits two stable ordered intermetallic phases, namely, L10 FeNi and L12 FeNi3, that are key issues to be tackled when creating a Fe–Ni potential consistent with thermodynamics. A procedure, based on a rigid lattice Ising model and the theory of correlation functions space, is developed to address all the intermetallics that are possible ground states of the system. While controlling the ground states of the system, the mixing enthalpy and defect properties were fitted. Both bcc and fcc defect properties are compared with density functional theory calculations and other potentials found in the literature. Finally, the potential is thermodynamically validated by constructing the alloy phase diagram. It is shown that the experimental phase diagram is reproduced reasonably well and that our potential gives a globally improved description of the Fe–Ni system in the whole concentration range with respect to the potentials found in the literature.

Phase diagrams of binary alloys calculated from a density functional theory

Phase behaviors of binary alloys with an embedded atom model potential are investigated using the thermodynamic perturbation theory. The free energies of the liquid and solid phases are computed using the fundamental measure density functional theory and accurate approximations to the hard-sphere mixture correlation functions. The method is applied to calculate the Au-Cu alloy phase diagram. To improve the accuracy of the computed phase diagram, we developed a systematic approach to optimize the model potential of Au-Cu by adjusting the melting temperature of the pure Au to its experimental one. With such an optimized potential the computed Au-Cu alloy phase diagram is in good agreement with the experimental one for the whole composition range.

Phase diagrams of advanced magnesium alloys containing Al, Ca, Sn, Sr, and Mn

In this paper an overview of the most relevant phase diagrams is given comprising the unconventional alloying elements Sn, Ca, and Sr, in reasonable combinations with Al and Mn in Mg alloys as a basis for advanced applications. The focus is on magnesium-rich partial projections of the liquidus surface of five ternary systems, relevant to technological applications for lightweight materials. All phase diagrams are calculated from a coherent thermodynamic multicomponent database for magnesium alloys. These calculations are validated by key samples in the pertinent subsystems, including extensive ternary assessments and also quaternary work. Isothermal sections of magnesium-rich phase diagrams of alloys with constant aluminum and manganese content at 500°C and 550°C are given for the two five-component systems: Mg-Al-Mn-Ca-Sr and Mg-Al-Mn-Ca-Sn.

Design and Optimization of S-Type Thermal Cutoffs

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A design and optimization procedure for S-type thermal cutoffs is presented in this paper. This type of cutoff is widely used for thermal protection of windings in motors and transformers and in boiling systems. Cutoff temperature is determined by the melting point of the alloy which is used for breaking the electrical circuit. A method for obtaining phase diagrams for ternary alloys by using 3-D surface modeling was developed. Composition of the ternary alloys for the desired melting point could be obtained by using this method. Construction of the thermal cutoffs for 95 <formula formulatype="inline"> <tex Notation="TeX">$^{\circ }{\hbox {C}}$</tex></formula> and 138 <formula formulatype="inline"><tex Notation="TeX">$^{\circ }{\hbox {C}}$</tex></formula> temperatures in terms of thermal, electrical, and mechanical properties is described. Design and optimization were carried out by using finite-element analysis (FEA) method for 3-D simulation of the devices' steady-state and transient behavior in coupled thermal and electrical domains. Technology for the production of experimental samples is also described. Characterization of the devices was done by using the thermovision technique and reasonable agreement with the simulation results was found. Further optimization steps based on the experimental data are suggested. </para>

Monte Carlo simulation of magnetic phase transitions in amorphous alloys of the Re-Tb system

The magnetic properties of amorphous alloys of the Re-Tb system and pure amorphous terbium have been investigated by the Monte Carlo method within the Heisenberg model. The temperature dependences of the spontaneous magnetization and magnetic susceptibility have been constructed for different ratios of the anisotropy constant to the exchange constant, D/J. The minimum value of D/J at which the spin-glass transition occurs is determined. The magnetic phase diagram of amorphous Re-Tb alloys, obtained by the simulation, is in qualitative agreement with the experimental data.

Thin layer in situ XRD of electrodeposited Ag/Sn and Ag/In for low-temperature isothermal diffusion soldering

In situ X-ray diffraction of thin electroplated Ag/Sn and Ag/In sandwich layers on Ni-coated copper substrates has been used to monitor the phase evolution in these systems at various temperatures. Initially, the course of the reactions in both systems, which are used in isothermal diffusion soldering, follows the transitions in their binary alloy phase diagrams. At 320 °C the composition of the reaction zone in the Ag/Sn case changes straightforward from tin-rich to silver-rich phases. In the case of Ag/In the same trend is observed, but the homogenization of the layer system is more complicated due to peritectic and metatectic reactions during heating up. The electroplated Ag/Sn and Ag/In ratios corresponded to the compositions of the respective ζ-phases. As the homogenization of the solder layers at 320 °C progressed, Ni–Sn and Ni–In phases were detected by EDX. The depletion of the Ag phases from Sn and In and formation of the solid solutions of Sn and In, respectively, in Ag were followed by in situ XRD. This technique allows studying the transformation of phases in thin layer sT:/PGN/ELSEVIER/META/web/00003803/ystems at process temperatures.

Discovery of Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloys in the Zhaishang gold deposit, southern Gansu Province and its geological significance

Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

Publisher's Note: Thermodynamic states and phase diagrams for bulk-incoherent, bulk-coherent, and epitaxially-coherent semiconductor alloys: Application to cubic (Ga,In)N [Phys. Rev. B77, 205201 (2008)

Publisher's Note: Thermodynamic states and phase diagrams for bulk-incoherent, bulk-coherent, and epitaxially-coherent semiconductor alloys: Application to cubic (Ga,In)N [Phys. Rev. B<b>77</b>, 205201 (2008)

A cluster line approach for composition rules of quasicrystals and bulk metallic glasses

This paper analyzes the structure and composition characteristics of ternary quasicrystals and bulk metalic glasses from the viewpoint of atomic clusters. It is pointed out that quasicrystals and bulk metallic glasses satisfy a cluster line rule. The cluster line refers to a straight composition line linking a specific cluster to the third element in a ternary alloy phase diagram. A ternary quasicrystal or bulk metallic glass composition is located at the intersection point of two cluster lines. Ternary quasicrystal and bulk metallic glass compositions can be the expressed with a cluster-plus-glue-atom model which can predict new ternary bulk metallic glasses.

Chapter 3 - Thin Epitaxial Films: Insights from Theory and Experiment

Publisher Summary This chapter discusses metastability and pseudomorphic growth, kinetics, strain in hetero-epitaxial growth, alloy phase diagrams and defects, metastability and Bain distortions, and interfaces in metallic multilayers—Pb–Nb and Ag–Nb. A suitable free energy, when monitored as a function of various parameters such as lattice parameters, temperature or pressure is a complicated function of many variables with possibly numerous local minima. Metastability that is discussed in this chapter has to do with the existence of such local minima. To crossover from one local minimum to a neighboring minimum, the system needs to overcome an energy barrier. Growth conditions clearly play a vital role in determining the resulting metastable phase. Transition metals provide a platform for studying metastable phases. A layer by layer, pseudomorphic growth (that is, in registry with the substrate) usually provides insight into numerous size, surface and interface dependent properties of metastable structures. Kinetic processes do not necessarily select the most stable, lowest energy state but the most easily (kinetically) accessible state. It is seen that surface diffusion and migration of atoms can play complicated roles in the kinetics of growth. Thin epitaxial films are known to exhibit a wide variety of fascinating fundamental properties because of the interplay of electronic structure, morphology, strain, and magnetism. Idealized, simple systems are highly desirable. A great deal of attention has been paid to Fe films grown on various metallic substrates, such as Fe/Cu, Fe/W and Fe/Mo. One major reason for this interest is the magnetism associated with Fe films, which may depend on the growth mechanism. There are details of Magnetic 3d metals, Epitaxially grown magnetic systems, epitaxially grown fcc Fe/Cu and Fe 16 N 2 films— experimental background: Fe nitrides, discussion of large Fe moments, Fe/Cr, and bcc Nickel grown on Fe and GaAs.

合金状態図の研究と新材料開発

合金状態図の研究と新材料開発