Al-Sb-Ti (Aluminum-Antimony-Titanium)

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Section II: Phase Diagram Evaluations

Al-Sb-Ti (Aluminum-Antimony-Titanium) V. Raghavan

[1997Kim] determined partial isothermal sections for this system at 1300 and 1100 °C.

Binary Systems The Al-Sb phase diagram [Massalski2] depicts the congruently-melting compound AlSb (B3-type cubic) at the midcomposition. An update on the Al-Ti system appears in this issue. A schematic partial Sb-Ti phase diagram [Massalski2] depicts seven intermediate compounds: TiSb2 (CuAl2-type tetragonal), TiSb (NiAs-type hexagonal), Ti6Sb5 (orthorhombic), Ti5Sb3 (orthorhombic), Ti2.5Sb (BiTi2-type tetragonal), Ti3Sb (Cr3Si-type cubic), and Ti4Sb (Ni3Sn-type hexagonal). Not all of these appear to be established as equilibrium phases.

which were given a final anneal at 1300 °C for 16 h or at 1100 °C for 1 week. The phase equilibria were studied by x-ray diffraction, electron probe microanalysis and differential thermal analysis. The partial isothermal sections constructed by [1997Kim] at 1300 and 1100 °C are redrawn in Fig. 1. A ternary compound ␶ (denoted ␾ by [1997Kim]) was found to be stable up to 1500 °C, with a homogeneity range of 11.0-17.1 at.% Al, 19.2-25.5 at.% Sb, and 63.065.4 at.% Ti. It has the D8m, W5Si3-type tetragonal structure, with a ⳱ 1.0447 to 1.0484 nm and c = 0.5239 to 0.5275 nm [1997Kim]. It forms tie-lines with Ti3Sb, (␤Ti), (␣Ti), and TiAl (␥) at 1300 °C and with Ti3Sb, (␤Ti), ␣2, and TiAl (␥) at 1100 °C.

References

Ternary Isothermal Sections With starting metals of 99.99% Al, 99.99% Sb, and 99.8% Ti, [1997Kim] prepared seven alloy compositions,

1997Kim: T. Kimura, H. Doi, K. Hashimoto, E. Abe, and Y. Isoda, Phase Equilibria in the TiAl-Rich portion of Ti-Al-Sb System at 1373 and 1573 K, Nippon Kinzoku Gakkaishi, (J. Jap. Inst. Metals) Vol 61 (No. 5), 1997, p 385-390 (in Japanese)

Fig. 1 Al-Sb-Ti partial isothermal sections at (a) 1300 and (b) 1100 °C [1997Kim]

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Journal of Phase Equilibria and Diffusion Vol. 26 No. 2 2005

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