High-temperature Solid Solution Research Articles

Ga-Based Alloys in Microelectronic Interconnects: A Review.

Gallium (Ga) and some of its alloys have a range of properties that make them an attractive option for microelectronic interconnects, including low melting point, non-toxicity, and the ability to wet without fluxing most materials—including oxides—found in microelectronics. Some of these properties result from their ability to form stable high melting temperature solid solutions and intermetallic compounds with other metals, such as copper, nickel, and aluminium. Ga and Ga-based alloys have already received significant attention in the scientific literature given their potential for use in the liquid state. Their potential for enabling the miniaturisation and deformability of microelectronic devices has also been demonstrated. The low process temperatures, made possible by their low melting points, produce significant energy savings. However, there are still some issues that need to be addressed before their potential can be fully realised. Characterising Ga and Ga-based alloys, and their reactions with materials commonly used in the microelectronic industry, are thus a priority for the electronics industry. This review provides a summary of research related to the applications and characterisation of Ga-based alloys. If the potential of Ga-based alloys for low temperature bonding in microelectronics manufacturing is to be realised, more work needs to be done on their interactions with the wide range of substrate materials now being used in electronic circuitry.

Resorption of Ca3 – xM2x(PO4)2 (M = Na, K) Calcium Phosphate Bioceramics in Model Solutions

The resorbability of bioceramics in the Ca3(PO4)2–CaNaPO4–CaKPO4 system is evaluated in an approach involving thermodynamic assessment of solubility and investigation of the dissolution kinetics in model media, in particular in citric acid solutions. Thermodynamic calculation indicates high solubility of the Ca5Na2(PO4)4, α-CaМPO4, β-CaKPO4, and β-СаK0.6Na0.4PO4 phases. Investigation of the dissolution kinetics of ceramics has made it possible to identify two distinct types of behavior of resorbable materials in weakly acidic solutions: with fast resorption kinetics in the case of the phases based on nagelschmidtite solid solutions and α-CaМPO4 disordered high-temperature solid solutions, and with a nearly constant, relatively low dissolution rate and a high solubility limit in the case of β-СaK1 – xNa x -based phases.

Effect of heat treatment on the microstructure and properties of Cu–0.6Cr–0.2Zr alloy induction coil in electromagnetic steel-teeming system

The Cu–0.6Cr–0.2Zr alloy has been used as a new coil material to improve the performance and service life of coils in an electromagnetic steel-teeming system. The purpose of this work was to improve the properties of the Cu–0.6Cr–0.2Zr alloy to satisfy the coil requirements of a high strength and a high conductivity. For studying the effect of heat treatment on the properties of Cu–0.6Cr–0.2Zr alloy, the copper alloy was exposed to heat treatments of cold deformation and aging after high-temperature solid solution. The effects of aging treatment on the properties of the Cu–0.6Cr–0.2Zr alloy at different cold deformations were examined by a tensile mechanical-property test, electrical-conductivity measurements, microstructure observations and SEM. The Cu–0.6Cr–0.2Zr alloy has optimal comprehensive properties after solution treatment at 960 °C for 1 h, and 50% cold deformation and aging at 450 °C for 6 h, and the hardness, strength, elongation and electrical conductivity reached 225.2 HV, 522.7 MPa, 8.3% and 89.5% IACS, respectively.

Phase Equilibria in the Ag2Te-SnTe-Sb2Te3 System and Thermodynamic Properties of the (2SnTe)1−x (AgSbTe2) x Solid Solution

Phase equilibria in the Ag2Te-SnTe-Sb2Te3 system were experimentally investigated by means of differential thermal analysis, powder x-ray diffraction techniques, microhardness and electromotive force measurements (EMF) of concentration chains with Ag4RbI5 solid electrolyte. A liquidus surface projection of the system, 700 and 400 K isothermal sections, as well as four vertical sections of the phase diagram were constructed. The primary crystallization fields of phases and homogeneity range of phases were also determined. The character and temperature of the various non- and monovariant equilibria were identified. The system includes a high-temperature cubic structured solid solution along the SnTe-“AgSbTe2” section, which partially (0-15 mol.% SnTe) decompose below 630 K. The partial molar thermodynamic functions of silver in alloys and standard integral thermodynamic functions of the (2SnTe)1−x (AgSbTe2) x (where x = 0.1; 0.2; 0.4; 0.6 and 0.8) solid solution were calculated based on the EMF measurements results.

Phase equilibria and decomposition of solid solutions in the YbTe–SnTe–PbTe system

Phase equilibria in the YbTe–SnTe–PbTe system have been studied using differential thermal analysis, X-ray diffraction, scanning electron microscopy, and emf measurements on YbTe concentration cells. We have mapped out a number of vertical sections, the 400-K isothermal section of the YbTe–SnTe–PbTe phase diagram, and projections of its liquidus and solidus surfaces. The results demonstrate that the system is characterized by the formation of a continuous series of high-temperature solid solutions with a cubic structure (NaCl type), which undergo decomposition below ~1050 K. At room temperature, the YbTe solubility in the Sn1–x Pb x Te solid solution system is ~33–35 mol %, whereas the extent of the YbTe-based solid solution series does not exceed 3 mol %.

The Ag2Te-SnTe-Bi2Te3 system and thermodynamic properties of the (2SnTe)1-x(AgBiTe2)x solid solutions series

Phase relations and ternary solubility of the binary and ternary compounds in the Ag2Te-SnTe-Bi2Te3 system were experimentally investigated by means of differential thermal analysis (DTA) and powder X-ray diffraction (PXRD) techniques, as well as microhardness and electromotive force measurements (EMF) of concentration chains with Ag4RbI5 solid electrolyte. Five isopleth sections SnTe-AgBiTe2, Ag2Te-0.5SnBi2Te4, [AgSn0.5Te]-AgBiTe2, 0.5SnBi2Te4-AgBiTe2 and [AgSn0.5Te]-Bi2Te3 and two isothermal sections at 300 and 800 K as well as liquidus surface projection of the system were constructed. The primary crystallization fields of phases and homogeneity range of binary and ternary phases were also determined. The character and temperature of the various non- and monovariant equilibria were identified based on solidifications behavior of several key alloys. The system includes high-temperature cubic structured solid solutions series (γ-phase) along the SnTe-AgBiTe2 section. The partial molar thermodynamic functions for silver in the (2SnTe)1-x(AgBiTe2)x (where x = 0.1; 0.2; 0.4; 0.6 and 0.8) solid solutions were calculated based on the EMF measurements results.

Influence of high temperature softening and solid solution on intergranular corrosion susceptibility of Super304H stainless steel

ABSTRACTThermos-mechanical processes were investigated to suppress the high intergranular corrosion sensitivity of Super304H austenitic stainless steel. The microstructure and grain boundary character distribution were characterised, respectively, by scanning electron microscope and electron backscatter diffraction analysis. The degree of sensitisation (DOS) was evaluated by the double-loop electrochemical polarisation reactivation test. The results show that the bulk primary Nb(C,N) particles were dissolved more into the matrix after high temperature softening at 1300°C for more than 30 min and the special boundaries (∑ ≤ 29) maintained at the same level as the as-received state after solid solution at 1150°C. The DOS was decreased after high-temperature softening and solid solution treatments, which was attributed mainly to the dissolution of primary bulk Nb(C,N) phase during high-temperature softening and the dispersive precipitation of the secondary fine Nb(C,N) phase during solid solution, which had effectively consumed carbon.

Influence of Nb content on grain size and mechanical properties of 18 wt% Cr ferritic stainless steel

The influence of Nb contents between 0.20 and 1.20wt% on the grain size and mechanical properties of 18wt% Cr ferritic stainless steel produced by investment casting was investigated. The average grain sizes of the three steels decreased apparently with increasing Nb content mainly due to the increasing number of pre-existing oxides formed at higher temperature, which were more likely to be the nuclei of heterogeneous nucleation. The thermodynamic analysis of Nb(C,N) formation was in conformity to the experimental result that the Nb(C,N) precipitates became larger with increasing Nb content. The as-cast specimen with the smallest grain size of steel C had the worse tensile strength and elongation in comparison with the as-cast specimens of steels A and B, mostly owing to the catenarian and dendritic Nb(C,N) particles distributed densely at the grain boundaries. The mechanical properties of specimens were not improved remarkably through high temperature solid-solution, whereas the mechanical properties of normalized specimens in the three steels were improved to different degrees. The coalescence and sparse distribution of smaller precipitates at grain boundaries after normalizing effectively weakened the local stress concentration arising from the reticular distribution of particles. The normalized specimen of steel A with 0.24wt% Nb still showed good mechanical properties. Normalizing at 850°C for 2h is the appropriate heat treatment for the 18wt% Cr ferritic stainless steel. The comparatively rational Nb content of the ferritic stainless steel is between 0.20 and 0.40wt% for investment casting production.

Evaluation of the tantalum-titanium phase diagram from ab-initio calculations

The thermodynamic properties of the Ta-Ti binary system below 900 °C are not well known. In particular, the location and shape of the solvus between the phase separation region at low temperatures and the solid solution at high temperatures are not well defined. In this study, we present a thermodynamic description for this system based on ab-initio calculations. The formation enthalpies of bcc and hcp solid solutions are estimated using the special quasi-random structures methodology and their vibrational free energy calculated by the quasi-harmonic Debye model. The excess energies of the solid solutions are fitted to a sub-subregular model and used to define the phase diagram of the binary system. It is shown that the current empirical assessment of the energies of the pure elements leads to a phase diagram that strongly departs from the known experimental features at low temperatures. An ab-initio guided correction of these energies is necessary to obtain correctly the low temperature phase separation and the high temperature solid solution. The predicted solvus of the phase diagram is qualitatively different from those previously reported for the Ta-Ti system. It exhibits a miscibility gap between two distinct bcc phases, similar to those that exist in the closely related binary systems Ta-Zr, Ta-Hf, Cr-Ti, Mo-Ti, V-Ti, and Ti-W.

Constitution of Alloys and Phase Diagram of the Hf–Ru–Rh System. IV. Liquidus Surface and Melting Diagram of the Partial Ru–HfRu–HfRh–Rh System

Using the data obtained in study of the as-cast Hf–Ru–Rh alloys in the range 0–50 at.% Hf and considering the solidus surface constitution, physicochemical analysis techniques are employed to construct for the first time the liquidus surface of the Ru–HfRu–HfRh–Rh partial system onto the composition triangle, the melting diagram, and the reaction scheme reflecting processes during crystallization of the alloys. It is shown that five surfaces of primary crystallization of a continuous series of solid solutions between isostructural (CsCl-type) phases formed by compound HfRu and its high-temperature modification (δ phase), ruthenium and rhodium solid solutions, as well as the e phase based on compound HfRh3 (AuCu3-type structure) and θ phase based on compound Hf3Rh5 (Hf3Rh5-type structure) are parts of the liquidus surface. Three invariant four-phase processes involving liquid take place at 1900, 1810, and 1720°C.

Phase diagram of the Ba3Y(PO4)3–BaRbPO4 system and solid solutions with α-BaRbPO4 structure in the quasi-ternary system YPO4–Rb3PO4–Ba3(PO4)2

The phase diagram of the Ba3Y(PO4)3–BaRbPO4 system has been determined experimentally using thermoanalytical, XRD and microscopic studies. There are two invariant points in the system: eutectic one with composition 48 mass% (70 mol%) BaRbPO4 melting at T = 1560 °C, and another eutectoid point at 1105 °C in the composition range of 90–95 mass% (96–98 mol%) BaRbPO4. The high-temperature solid solution of Ba3Y(PO4)3 in α-BaRbPO4 (αss) exists above 1105 °C. The maximum concentration of Ba3Y(PO4)3 in this solution is about 5 mass%.The concentration ranges in which the high-temperature solid solution with the α-BaRbPO4 structure forms in the quasi-ternary YPO4–Rb3PO4–Ba3(PO4)2 system have been determined. The formation probability of this solution is related to the structure similarity of the initial phosphates constituting this phase.

Phase Transformations during Laser Processing of Aerospace Metallic Materials

Phase transformations in laser processed metallic materials usually occur under very high temperature gradients and during a short time. Therefore, laser materials processing has been usually associated to high heating and cooling rates. However, before understanding the temperature evolution of the target, the absorptivity and the optical penetration must be considered. This paper presents some conjectures about the how the metal absorbs the laser radiation and how rapid phase transformations take place. It would be proposed that the interface response functions could be a possible way to understand phase transformations from liquid or high temperature solid solution conditions. Finally, it will be presented some results about laser processed materials of aerospace interest: steels, titanium and aluminium, which will illustrate the practical applications of the theories.

Mineral associations and major element compositions of base metal sulphides from the subcontinental lithospheric mantle of NE Spain

This study deals with textural types and major element compositions of Cu-Ni-Fe sulphides from spinel lherzolite, harzburgite and olivine websterite xenoliths found in alkali basaltic rocks of the Neogene-Quaternary volcanic zone of Catalonia (NE Spain). Sulphides in harzburgites and websterites are scarce. Four textural types have been distinguished: inclusions in silicates and spinel, trails of small droplets often radiating from inclusions, interstitial grains, and grains related to pyrometamorphic textures. The mineral associations are dominated by one or two low-temperature monosulphide solid solutions: mss1, mss2, occasionally accompanied by pyrrhotite, pentlandite and Cu-rich sulphides. Compositions of mss1 are more Fe-enriched in inclusions and interstitial grains than in grains related to pyrometamorphism. Compositions of mss2 are Ni-rich very close to pentlandite. Sulphide bulk compositions correspond to high-temperature monosulphide solid solution equilibrated with a relatively Cu-Ni enriched sulphide melt at 1100–1000 °C. The breakdown products of these earlier compositions could have been either equilibrated below 600, 300 °C or being at disequilibrium. A restitic origin is consistent with the main sulphide mineral associations, the estimated melt extraction for peridotites (<30 %) and with the fact that lherzolites are less affected by cryptic metasomatism than harzburgites. However, Ni exchange coefficients between olivine and the high-temperature monosulphide solid solution underestimate equilibrium values. This suggests that some lherzolites could derive from pervasive refertilization. The scarcity of sulphides in websterites is explained by S incompatible behaviour during the formation of earlier cumulates from the mafic alkaline magmas which caused the cryptic metasomatism.

The Evolution of Microstructure and Texture during Thermomechanical Processing of Al-Mg-Si-Cu Alloy

In order to improve formability, it is practicable to control the texture through adjusting process parameters. This work describes the evolution of microstructure and texture during thermomechanical processing of Al-Mg-Si-Cu alloy. With the change of deformation conditions, both the microstructure and texture change dramatically. After hot rolling from 90 mm to 7.5 mm, H and E texture components in the surface layer become dominant due to non-uniform deformation. And then with the increasing of cold rolling deformation from 7.5 mm to 4.0 mm, the texture components gradually change from shear texture to typical fcc texture, i.e. Copper, S and Brass textures, and their intensities also increase. And these texture components transform to some uncommon texture components after intermediate annealing, including {013}&lt;001&gt;, {001}&lt;130&gt;, Goss texture, {556}&lt;110&gt; and {111}&lt;110&gt; texture, not as the typical recrystallization texture components. Continually giving a cold rolling deformation from 4.0 mm to 1.0 mm, not only Copper, S, Brass textures, but also Goss texture due to the lower deformation can be found in the alloy sheet. The high temperature solid solution treatment can result in the complete recrystallization and the formation of recrystallization texture, Cube, Goss and R texture, which results in the high formability of experimental alloy.

The revised phase diagram of the Ca3(PO4)2–YPO4 system. The temperature and concentration range of solid-solution phase fields

A revised version of the Ca3(PO4)2–YPO4 phase diagram has been proposed on the basis of results obtained by thermal analysis (DTA/DSC/TG) and X-ray diffraction methods. A limited solid solution with the structure of β-Ca3(PO4)2 exists in the system. At 1,100 °C the maximal concentration of YPO4 in the solid solution is ~15 mass%. The solid-solution phase field exists in the temperature range upto ~1,380 °C. Two high-temperature solid solutions with the structure of α′ and α-Ca3(PO4)2 form in system as well, however only the α phase can be obtained by quenching from high temperatures. The Ca3Y(PO4)3 compound with the structure of eulytite forms in the Ca3(PO4)2–YPO4 system at temperatures exceeding 1,255 °C and does not show any polymorphic transition.

Enthalpies of formation of Fe-Ni monosulfide solid solutions

Binary and ternary sulfides in the Fe-Ni-S system are of major fundamental and practical interest in environmental, geological, and planetary science. Despite extensive thermodynamic modeling of phase equilibria, the enthalpies of formation of solid solutions in this system have not been measured directly as functions of both nickel/iron and metal/sulfur ratios. This communication reports enthalpies of formation of Fe-Ni monosulfide solid solutions [ mss = (Fe 1−x Ni x ) 1−z S, 0 ≤ x ≤ 1; 0.875 ≤ 1−z ≤ 1] quenched from 750 °C, representing disordered structural states. Measurements were performed on three series of solid solutions using oxidative solution calorimetry in molten sodium molybdate solvent at 702 °C. The measured enthalpies of formation of Ni 1−z S solid solutions from elements are consistent with prior data reported for a few compositions. The enthalpies of formation of ternary compositions, (Fe 1−x Ni x ) 1−z S, are reported for the first time. Within their uncertainties, the enthalpies of formation of the solid solutions, quenched from high temperature, with respect to the end-members (enthalpies of mixing) at 25 °C are zero. An experimentally derived equation is proposed for the calculation of enthalpies of formation of all high-temperature monosulfide solid solutions in the Fe-Ni-S system. The thermodynamic stabilization of these disordered solid solutions arises not from energetic terms but from the configurational entropy.

The Feasibility Research on Producing Lightweight Aggregates Made from the Waste Stone Sludge

This paper aims to investigate on producing lightweight aggregates made from the waste stone sludge. It was utilizing the mechanism of high temperature solid solution method as well as in coordination with the production method of reservoir sediments lightweight aggregates to conduct an investigation on the development of lightweight aggregate using stone sludge. The investigation shows that the analysis results for the stone sludge are not in the limits of the expandable region of the ternary diagram due to the high content of FeOx. That caused the expandable temperature range was narrow, the expandability of aggregate was poor and the aggregate particle density was relatively high. But, it still could be producing lightweight aggregates made from the waste stone sludge in this paper. The better solution may be to add the high-content organic materials to adjust chemical composition, such as water purification sludge, sewer sludge, reservoir sludge etc.

Sulfide-rich dunite within a thick Moho transition zone of the northern Oman ophiolite: Implications for the origin of Cyprus-type sulfide deposits

Peculiar dunites, in part wehrlitic, that contain up to 3vol.% sulfides from a thick (~1000m) Moho transition zone (MTZ) are found along Wadi Thuqbah in the northern Oman ophiolite. We discuss their relevance to the formation of Cyprus-type massive sulfide deposits near the surface. Field observations suggest that the sulfide-rich MTZ dunites are of late-intrusive origin. The sulfides form composite grains with magnetite and form angular clasts, which are enclosed or cut by magnetite. The sulfide part is composed of homogeneous pyrrhotite and vermicular intergrowth of pyrrhotite and pentlandite. Sulfide inclusions in clinopyroxene comprise pyrrhotite with pentlandite blebs, free of magnetite. Olivines in the sulfide-rich dunite characteristically show low NiO contents (0.1–0.3wt.%) relative to a high Fo value (~91), and as such they do not lie on a Fo–NiO trend of ordinary sulfide-free MTZ dunites–wehrlites. This low-Ni olivine was precipitated from a high-Mg magma that had segregated Ni-rich sulfide melts. The pentlandite–pyrrhotite intergrowth was formed by subsolidus exsolution at low temperatures (<200°C) from high-temperature mono-sulfide solid solution. Iron released from olivine during serpentinization produced magnetite, which was combined with the sulfides to form the composite grains. In-situ S isotope ratios of the sulfides (δ34S=0.7–2.8) are slightly higher than mantle values but lie within the range for magmas from oceanic island arcs, such as the Marianas. The δ34S are lower than those for sulfate from seawater and MORB-related sulfides, such as TAG (Trans-Atlantic Geotraverse) deposits. One of the Cyprus type massive sulfide deposits (Aarja) from the crustal section of the same area shows similar S isotope ratios to the sulfides in the Thuqbah sulfide-rich dunites/wehrlites, indicating their genetic linkage. The Aarja sulfide deposit was formed within the V2 lavas, which are relatively sulfur-rich and of an off-axis origin, as a result of high-temperature seawater circulation. The Thuqbah sulfide-rich dunite possibly represents an igneous root of the Cyprus-type massive sulfide deposit of Aarja formed in an off-ridge magmatic-hydrothermal system.

A combinatorial approach to microstructure and thermopower of bulk thermoelectric materials: the pseudo-ternary PbTe–Ag2Te–Sb2Te3 system

The microstructures and Seebeck coefficients of thermoelectric alloys in the pseudo-ternary PbTe–Ag2Te–Sb2Te3 system were examined using samples that were compositionally graded by unidirectional solidification by the Bridgman method and diffusion couples. At compositions near the middle of the pseudo-binary PbTe–AgSbTe2 line, a compositionally modulated microstructure has been found. From diffusion couple experiments, it is found that the PbTe–AgSbTe2 system exhibits a miscibility gap at low temperatures while it forms a complete solid solution at high temperatures; the critical temperature is between 400 °C and 450 °C. The modulated microstructure originates from the decomposition of the high-temperature solid solution during cooling. Scanning Seebeck coefficient measurement on these samples covers a wide compositional space of the pseudo-ternary system. The Seebeck coefficient transitions from positive values at AgSbTe2-rich compositions to negative values at PbTe-rich compositions on the pseudo-binary PbTe–AgSbTe2 line. Composition-graded samples prepared by the Bridgman method are thus useful to investigate thermoelectric materials in multi-component systems.

Microcontinents among the accretionary complexes of the Central Asia Orogenic Belt: In situ Re–Os evidence

Major elements and Re–Os isotope ratios were analysed in situ on individual sulfide grains in spinel peridotite xenoliths hosted by Quaternary intraplate basalts from the Tariat volcanic field, Central Mongolia. The sulfides are dominantly high-temperature (>900°C) Fe-rich monosulfide solid solution (MSS). Some sulfides with low Ni contents may be residual MSS, whereas other sulfides defining a negative Ni–Cu correlation may be crystallization products of fractionated sulfide melts. The subchondritic 187Re/188Os and 187Os/188Os of some sulfides also indicate they are residual MSS. Os isotope compositions of sulfides reveal the presence of Archean to Proterozoic lithospheric mantle beneath the region. The sulfides have TRD model ages ranging from 3.0 to 0.2Ga, with peaks at 1.5–1.3, 1 and 0.7–0.5Ga. The peak ages are indicative of significant events in the lithospheric mantle at those times. The timing of these events is remarkably consistent with those of the major crust-building events within the Tarvagatay Terrane where the Tariat volcanic field is located. The similarity in the ranges of crustal U–Pb ages and Nd model ages, and our sulfide Os model ages, suggests that the sulfide ages may date metasomatic events in the underlying lithospheric mantle, which were related to tectonothermal events that affected the overlying crust. Radiometric ages from the Tarvagatay Terrane appear to correspond to the Archean model ages from its SCLM counterpart. The last two events (1.1 and 0.7–0.5Ga) recorded in the Tarvagatay Terrane suggest involvement of the “CAOB mantle” and development of significant juvenile crustal growth in the orogeny.