The 900 °C isothermal section of Ti-Ni-V alloys

Abstract

The AB 2 -type Ni-based alloys are the most prominent candidates as electrode materials in the recent development of Cd-free rechargeable batteries. [1] Most of these developing AB 2 alloys are multicomponent alloys, and the Ti-Ni-V ternary system is one of the most important base systems for the AB 2 electrode alloys. The three constituent binary systems, Ti-V, Ni-Ti, and Ni-V, have been studied earlier. [2,3,4] Ti-V is an isomorphous system with a continuous solid solution at high temperatures and there is a monotectoid reaction at 675 ЊC. [2] For the Ni-Ti binary system, there are Fig. 1-Chemical compositions of alloys examined in this study superimthree compounds, Ti 2 Ni, TiNi, and TiNi 3 . [3] Five compounds, posed on the isothermal section of the Ti-Ni-V ternary system at 900 ЊC.Ni 8 V, Ni 3 V, Ni 2 V, (Ј), and NiV 3 , have been found in the Ni-V system. [4] Eremenko et al.'s report [5] is the only report available for experimental investigation of the phase equilibria of the ternary Ti-Ni-V system. They reported a partial 900 ЊC isothermal section of the Ti-rich side, and no ternary compounds were reported. In the present study, experimental examination has been conducted to complete the determination of the isothermal section of the Ti-Ni-V system at 900 ЊC.Proper amounts of Ni, Ti, and V were weighed and placed in a Cu crucible in the arc melter. The chamber of the melter was purged with argon gas to reduce possible oxidation of the alloys. The metal pieces were arc melted together and a button-shape Ni-Ti-V alloy was formed. The button was flipped upside down and remelted in the arc melter at least five times to assure its compositional homogeneity. The alloy button was taken out of the arc melter and weighed to assure Fig. 2-X-ray diffraction peaks of Ti-V alloys of various compositions.that there had been no noticeable weight changes after the arc melting. The button was then encapsulated in an evacuated quartz tube. The sample tubes were heat treated at 900 ЊC forms a continuous (␤ Ti,V) solid solution at 900 ЊC. The in a tube furnace for 168 to 240 hours before they were lattice constant, a, of Ti is 0.33066 nm and that of V is quenched in ice water. The quenched alloys were cut into 0.30282 nm. [2] According to Vegard's law, [6] lattice constants half. One part was prepared for X-ray diffraction analysis, of the solid solutions can be calculated and then the diffracand the other part was examined by using metallography tion angles can be determined. As shown in Table II, the and sometimes electron probe microanalysis (EPMA) and experimental measurements and the calculations are in scanning electron microscopy. good agreement. Five Ti-V alloys (alloys 1 through 5) were prepared fol- Figure 3 displays the microstructure of the Ti-10 at. pct lowing the aforementioned procedures and were annealed Ni-10 at. pct V alloy (alloy 6) annealed at 900 ЊC for 168 at 900 ЊC. Nominal compositions of these alloys are listed hours. Two phases are observed. An etching solution of the in Table I and shown in Figure ...

Microstructures, Thermal and Tensile Properties of Sn-Zn-Ga Alloys

“…In addition, the Sn-Zn alloys examined in this study exhibited a higher enthalpy of fusion in comparing with eutectic Sn-Pb and Sn-Ag solders. 19) The cooling curves of the specimens, Fig. 7, indicate that all the samples show a eutectic feature and no inflection point above the eutectic temperature.…”

“…25) At a small addition of Ga (less than 0.25 mass%), Ga atoms tend to segregate at the cell boundary regions. The segregation of Ga breaks up the interface between the cells and Enthalpy of fusion, h/J/g 0Ga 0.5Ga 1.0Ga 1.8Ga Sn-Ag [19] Sn-Pb [19] Sn-Zn [11] (b) A further increase in Ga content converts the eutectic structure to a part-normal and part-irregular structure. This phenomenon is attributed to the composition variation of the solidification front.…”

Thermal Characteristics and Intermetallic Compounds Formed at Sn-9Zn-0.5Ag/Cu Interface

“…4 C respectively, which are very close to the previous published results. 16,22) When 0.5 mass% Ag is added to the Sn-9Zn solder alloy, the T onset of the solder alloy increases from 195. 5 to 196.7 C and the increment of 1.2 C is acceptable.…”

“…Chen et al 16) have demonstrated that the Sn-37Pb solder alloy melts at 183 C and the enthalpy of fusion is 45.2 J/g. The melting point of the solder alloy reported by Chen et al 16) is close to our result, but the fusion heat is only one half of ours, because the K value of the DSC instrument has not been calibrated in the former study.…”

“…[7][8][9] The Sn-9Zn and Sn-3.5Ag are the two important binary lead-free solders investigated, 10,11) but inferior wettability and oxidation resistance of the Sn-9Zn alloy and high melting point (221 C) of the Sn-3.5Ag alloy, limit the usage of these solder alloys. [12][13][14][15] Chen et al 16) have determined the melting and solidification characteristics of various solder alloys using DSC. Besides the binary alloys, ternary solder alloys are also considered as a substitute for the Sn-37Pb solder alloy.…”