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JPEDAV (2005) 26:639-640 DOI: 10.1361/154770305X74610 1547-7037/$19.00 ©ASM International

Al-Ti-V-Zr (Aluminum-Titanium-Vanadium-Zirconium) V. Raghavan

The information on this system is limited to the pseudoternary sections at 1100, 1000, and 900 °C on the Al3TiAl 3 V-Al 3 Zr plane of the composition tetrahedron [1996Par].

Binary Systems For brief descriptions of the Al-Ti, Al-V, and Ti-V phase diagrams, see [2005Rag]. The Al-Zr phase diagram depicts ten intermediate phases [Massalski2]. For the limited purpose of this review, we need only to note that Al3Zr has the D023-type tetragonal structure. There are no intermediate phases in the Ti-Zr system. ␤Ti and ␤Zr form a continuous body-centered cubic (bcc) solid solution. ␣Ti and ␣Zr form a continuous hcp solid solution. The V-Zr phase diagram [1989Smi] shows one intermediate phase: V2Zr, which has the C15, MgCu2-type cubic structure.

of Al3Ti. The effect of Zr addition on the (␣Ti)-(␤Ti)-␥ (TiAl) phase equilibria at 1300, 1200, and 1000 °C was reported by [2000Kai]. In the Al-V-Zr system, the Al3V-Al3Zr pseudobinary section was determined by [1996Par] (Fig. 2). Al3V dissolves between 10 and 20 mol% Al3Zr, whereas the solubility of Al3V in Al3Zr is less than 5 mol%. [1992Eno] reviewed the Ti-V-Zr system, presenting a liquidus surface, a reaction scheme, and an isothermal section at 750 °C.

Quaternary Phase Equilibria

For an update of the Al-Ti-V system, see [2005Rag]. In the Al-Ti-Zr system, the Al3Ti-Al3Zr pseudobinary section determined by [1996Par] is shown in Fig. 1. The Al3Tibased D022 structure dissolves a few mol% Al3Zr, whereas the Al3Zr-based D023 structure dissolves more 80 mol%

With starting metals of 99.99% Al, 99.9% Ti, 99.8% V, and 99.8% Zr, [1996Par] arc-melted in vacuum four quaternary alloys with a fixed Al content of 75 at.%. The alloys were annealed at 1300-1100 °C for 24-72 h and quenched in water. The phase equilibria were studied with scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy. The experimental data were used to derive the interaction parameters for the D022 and D023 solid solutions and to calculate the pseudoternary sections at 1300, 1200, and 1100 °C on the Al3Ti-Al3V-Al3Zr plane of the composition tetrahedron. A composite computed diagram in Fig. 3 depicts the phase boundaries on this section at the above three temperatures. As the temperature decreases, the (D022 + D023) two-phase field expands, with the D023 phase field remaining almost unchanged.

Fig. 1 Al-Ti-Zr pseudobinary section along the Al3Ti-Al3Zr join [1996Par]

Fig. 2 Al-V-Zr pseudobinary section along the Al3V-Al3Zr join [1996Par]

Ternary Systems

Journal of Phase Equilibria and Diffusion Vol. 26 No. 6 2005

639

Section II: Phase Diagram Evaluations

Fig. 3 Al-Ti-V-Zr pseudoternary sections at 1100, 1000, and 900 °C on the Al3Ti-Al3V-Al3Zr plane [1996Par]

References 1989Smi: J.F. Smith, The V-Zr System, Phase Diagrams of Binary Vanadium Alloys, ASM International, 1989, p 326329 1992Eno: M. Enomoto, The Ti-V-Zr (Titanium-