Ternary Eutectic Alloy Research Articles

The Mechanical Properties of Unidirectionally Solidified Zn-Al Binary Eutectic and Zn-Al-Cu Ternary Eutectic Alloy Castings

The Mechanical Properties of Unidirectionally Solidified Zn-Al Binary Eutectic and Zn-Al-Cu Ternary Eutectic Alloy Castings

Phase Stability and Mechanical Behavior of Ternary Bismuth-Lead-Tin Solders

AbstractResults from a phase stability study of the Bi-Pb-Sn ternary system and mechanical property data from the testing of the Bi-Pb-Sn ternary eutectic alloy are reported. It is found that the mechanical properties of the ternary eutectic alloy change considerably during cooling due to a solid state phase change at 79° C. After solidification, but prior to this phase transformation, the alloy exhibits brittle failure upon tensile loading. After the phase change high ductility is observed, bordering on superplasticity at low strain rates. Furthermore, having gone through the phase change once, the alloy remains ductile even after it is held at temperatures above 79° C. These results are interpreted in terms of the microstructures observed in the alloy.

Microstructures of directionally frozenin situ composites of multicomponent eutectics

Microstructural variations of binary (Sn-Pb, Sn-Cd, Pb-Cd), ternary (Sn-Pb-Cd) and quaternary (Sn-Pb-Cd-Zn) eutectics which were permitted to solidify directionally were investigated in terms of the controlled solidification rates. It was found that, at an appropriate freezing rate, the structure was lamellar and satisfied the Jackson-Hunt relationship, and furthermore, that the order of the layers present in the solidified eutectics was definite, such that in the case of Sn-Pb-Cd ternary eutectic alloy, for instance, the Sn-Cd layers would not be allowed to be in contact. An explanation for this could be the high interfacial energy between the two.

Microstructure of one of the ternary eutectic alloys in the Bi-In-Sn system

Two ternary eutectic alloys are known to exist in the Bi-In-Sn ternary system. Experiments were conducted to determine the phases present, the structure, and the volume fraction of each phase in one of the two eutectics. The eutectic investigated melted at 332 K and had a composition of 31.6 wt pct Bi, 48.8 wt pct In, and 19.6 wt pct Sn. The phases present are the major phase BiIn2, the β phase of the In-Sn system, and the γ phase of the In-Sn system. The structure consists of the major phase in which are embedded fibers of the two minor phases. The measured volume fractions of the phases are approximately 56 pct BiIn2, 24 pct β, and 20 pct γ. The volume fraction of the two minor phases (44 pct) in the eutectic is well above the percentage of fibrous phase usually found in binary eutectics.

Microstructure of ternary eutectic alloys in Bi-Cd-In system

Abstract Two ternary eutectic reactions are known to occur in the Bi-Cd-In ternary system: one takes place at 334.6 K and the other at 350,6 K. Experiments were conducted to determine the microstructures that result from these eutectic reactions, as well as the phases present and the volume fraction of each phase. The phases present in the 334.6 K eutectic are the major phase (BiIn2), Cd solid solution, and an In rich phase which subsequently decomposes eutectoidally. The room temperature In phase is α In. Lamellae of both minor phases are embedded in the major phase with a configuration ABCBA…, similar to that of the Cd-Pb-Sn ternary eutectic. A represents the BiIn2 phase, B the In rich phase, and C the Cd rich phase. The measured volume fractions are 60%BiIn2 4%Cd, and 36% In rich phase. The phases present in the 350.6 K eutectic are BiIn2, BiIn, and Cd solid solution. The structure, which is not regular, consists of the major phase (BiIn2) in which are embedded perforated plates of the BiIn phase and t...

A study of a cellular phase transformation in the ternary Ni- Ai- Mo alloy system

Orthorhombic Ni3Mo has been observed as a product of a cellular precipitation reaction occurring at grain boundaries in both Ni-12Al-15Mo and a ternary eutectic Ni-12.8Al-22.2Mo (compositions in at. pct) when heat treated at intermediate temperatures (600 to 850 °C). Convergent beam electron diffraction and energy dispersive X-ray spectroscopy techniques have been employed to characterize the structure and composition of this phase in these alloys. Since this phase is usually heavily faulted, the diffraction symmetries are reduced, causing ambiguities in analysis. Therefore, a binary (nominally) stoichiometric Ni3Mo alloy was produced and heat treated in a manner designed to minimize faulting. Convergent beam patterns obtained from this material exhibited symmetries that identify it as having the mmm point group; further analysis of the diffraction patterns led to the conclusion that the space group is Pmmn. These patterns were then used to aid in the interpretation of those taken from the ternary alloys. Orthorhombic Ni3Mo was also observed within the grains of the ternary eutectic alloy following prolonged aging treatments; the orientation relationship between the Ni3Mo and the fee matrix was determined to be identical with that in the cellularly transformed regions.

Controlled Collapse Reflow for Josephson Chip Bonding

The scheme of controlled collapse reflow chip joining has been investigated again and extended to the package of Josephson device chips. Low temperature ternary eutectic (In/Bi/Sn) alloy is selected as the solder material which melts at 60°C. An interface metallurgy of Pd/Au was used as an interface layer bridging superconducting Nb pads and the solder. Indium stand‐offs are used for controlling collapse and providing constant spacing between chips and carrier modules. Mechanical and electrical test vehicles were fabricated and evaluated.

Cantilever-type displacement sensor using diffused silicon strain gauges

Two kinds of alloys have been developed as cantilever and solder materials which are suitable for semiconductors. The cantilever material is an ironnickelcobalt ternary alloy that has a high elasticity with a tensile strenght of 1GPa, and a low thermal expansion coefficient 50 × 10 −7/K. The material for the solder is goldcoppergermanium ternary eutectic alloy that has a tensile strength of 1.1 GPa. Two strain gauges were diffused in parallel on a silicon pellet, and the pellet was bonded by the alloy solder on each surface of the cantilever, taking into account linearity and temperature effect. It was confirmed that the linearity was less than ±0.1% and a zero-point shift was under ±0.1% after 10 7 repeated stresses. The temperature effect was less than ±05% over a range of 230 – 390K using a non-linear compensation.

Superplasticity in the Pb-Sn-Zn and Pb-Sn-Cd ternary eutectic alloys

Superplastic behaviour has been examined in the Pb-Sn-Zn and Pb-Sn-Cd ternary eutectic alloys. Both alloys exhibited log σt/log εt and m/log εt relations similar to those of comparative binary eutectic alloys. Activation-energy values and metallographic observations indicated that the deformation mechanism was consistent with grain-boundary sliding. It was also concluded that the multiplicity of types of interphase boundary does not play a significant part in determining superplastic behaviour.

Microstructure and mechanical properties of unidirectionally solidified Al-Si-Ni ternary eutectic

Al-10.98 pct Si-4.9 pct Ni ternary eutectic alloy was unidirectionally solidified at growth rates from 1.39μm/sec to 6.95μm/sec. Binary Al-Ni and Al-Si eutectics prepared from the same purity metals were also solidified under similar conditions to characterize the growth conditions under the conditions of present study. NiAl3 phase appeared as fibers in the binary Al-Ni eutectic and silicon appeared as irregular plates in the binary Al-Si eutectic. However, in the ternary Al-Si-Ni eutectic alloy both NiAl3 and silicon phases appeared as irregular plates dispersed in α-Al phase, without any regular repctitive arrangement. The size and spacing of NiAl3 and Si platelets in cone shaped colonies decreased with an increase in the growth rate of the ternary eutectic. Examination of specimen quenched during unidirectional solidification indicated that the ternary eutectic grows with a non-planar interface with both Si and NiAl3 phases protruding into the liquid. It is concluded that it will be difficult to grow regular ternary eutectic structures even if only one phase has a high entropy of melting. The tensile strength and modulus of unidirectionally solidified Al-Si-Ni eutectic was lower than the chill cast alloys of the same composition, and decreased with a decrease in growth rate. Tensile modulus and strength of ternary Al-Si-Ni eutectic alloys was greater than binary Al-Si eutectic alloy under similar growth conditions, both in the chill cast and in unidirectionally solidified conditions.

Superplasticity in the ternary eutectic alloys AL-33WT%CU-7WT%MG and AL-25WT%CU-11WT%MG

Superplasticity in the ternary eutectic alloys AL-33WT%CU-7WT%MG and AL-25WT%CU-11WT%MG

A High Resolution Dynamic Technique of Thermoelectric Power Measurements

A new technique, principally applicable to metals and alloys, has been developed for high resolution absolute thermoelectric power (TEP) and differential thermoelectric power measurements. It utilizes two continuously monitoring dc nanovolt amplifiers, one for the sample couple thermoelectric voltage and the other for a thermocouple voltage proportional to temperature differences developed across the samples. The outputs of these amplifiers are attached to the channels of an X-Y recorder, thus yielding direct slope-proportional data. By using heat from a low-mass, electrostatically guarded heater to develop transient temperature gradients across samples, it is possible to dynamically determine the absolute TEP of a sample versus lead (Pb) or the differential TEP of two nearly similar samples, one of whose composition or history of treatment has been slightly altered. Reducing thermal time constants with an independent heat leak permits the completion of a TEP measurement in a few seconds, thus yielding high resolution determinations under adverse experimental conditions. The use of a special sample necking and ``heat sinking'' techniques, as well as a low melting point, low TEP, ternary eutectic indium alloy solder, make it possible to obtain results with a range of high resolutions. The experimental resolution attainable with these two dynamic techniques can be summarized as ±[10−3)(ΔT)−1(μV/K)+1.0%] for absolute TEP and ±[ΔT)−2+Sabsolute2]1/2 10−3(μV/K) for differential TEP, where ΔT is the range 0.01–1.0 K increment of differential temperature and Sabsolute is the approximate value of the thermopower of one of the samples. Data utilizing this newly developed technique are presented on Chromel-P, Wood's metal solder, and the ternary eutectic InSnCd solder alloy, as well as differential TEP measurements of two opposing Chromel-P samples over the temperature range of T = 1.5–300 K.

Al-CuAl<SUB>2</SUB>層状共晶と繊維状共晶とを組合わせた3元共晶合金の一方向凝固組織

Ternary eutectic alloys, Al-CuAl2-NiCu3Al6, Al-CuAl2-FeCu2Al7 and Al-CuAl2-Si, consisting of Al-CuAl2 lamellar eutectics and Al-Al3Ni, Al-Al3Fe or Al-Si fibrous eutectics, were solidified unidirectionally over a wide range of rates. These microstructures are compared with those of concomitant binary eutectics and are discussed with reference to the term of entropy of fusion of each phases. In Al-CuAl2-Si ternary eutectics, Si grows with prefered 〈100〉 fiber texture as in Al-Si binary eutectics, though Al-CuAl2 lamellar are degenerated thoroughly. This is considered to come from the difference of entropy of fusion between Si and CuAl2, because the entropy of fusion of Si is higher than that of CuAl2. On the other hand, in Al-CuAl2-NiCu3Al6 ternary eutectics, Al-CuAl2 lamellae are maintained because the difference in the entropy of fusion between NiCu3Al6 and CuAl2 is smaller than that of Si and CuAl2. It may be concluded that with increasing entropy of fusion of the third phase, the influence of Al-CuAl2 on the Al-CuAl2 lamellae becomes greater.

Al-Si系を中心とした3元共晶合金の一方向凝固組織

Al-Si系を中心とした3元共晶合金の一方向凝固組織

THE SYSTEMS ALUMINUM-TIN AND ALUMINUM-LEAD-TIN

The solubility of tin in aluminum, between 400° and 645 °C, has been determined by an isothermal method. The system Al–Pb–Sn has been investigated, isothermally, at 500° and 600 °C. The eutectic temperature and composition of this system have also been determined. The structure of the phases in completely solid alloys has been identified by photomicrography. The liquidus curves at 500° and 600 °C. are continuous, extending across the ternary diagram from the Al–Pb system to the Al–Sn system. On neither of the two isotherms does a two-liquid region occur, despite the fact that a well-defined two-liquid region exists at temperatures above 650 °C. This was found to be due to inaccuracy in the published diagram for the Al–Sn system and this led to the work mentioned above. The solubility of tin in aluminum is much less than it has been supposed and this causes the surface of solid aluminum to intrude into the solid diagram at an early stage, thus blocking out the two-liquid region. The ternary eutectic temperature is 183.0 °C. and the composition, 0.08 weight per cent Al, 38.1% Pb, and 61.7% Sn. In any alloy at room temperature, the solid phases are: primary aluminum, α-lead, and β-tin. Brinell Ball and Vickers Diamond Pyramid hardness tests show that the ternary eutectic alloy is the hardest of the system. When alloys approximating to the eutectic composition are used as solders, it has been found that the alloy of ternary eutectic composition has a greater shear strength than ordinary solder.