Phase equilibria in the α-Ti-Al-Si region of the Ti-Si-Al system

Abstract

An experimental investigation of the phase relations in the titanium (Ti)-aluminum (Al)-silicon (Si) system was undertaken by differential thermal analysis, x-ray diffraction, metallography, and microprobe analysis. The present measurements when combined with those from an earlier investigation at this laboratory provide data for 56 alloy compositions in the Ti-Al-Si system. The combined results allowed the construction of a solidus projection, a melting diagram including both solidus and liquidus, partial isothermal sections at 1270°C and 1250°C, three isopleths with a constant percentage of one or another component, and a reaction scheme. along the Si-Al side of the ternary system was studied by Kamei et al. [1968Kam] andZakharov et al. [1988Zak]. According to Kamei et al. [1968Kam], two invariant equilibria occur in this part of the system: peritectic L + TiAl 3 ↔ TiSi 2 Al + Al; and eutectic L ↔ TiSi 2 Al + Al + Si. The reaction temperatures were not given. Two peritectic equilibria were reported by [1988Zak]: L

The Ti5Si3–Tb5Si3 section of the Ti–Tb–Si system

“…The alloy compositions, heat treatment conditions, phase composition of the samples and chemical com- [4] with corrections of [5,6]; (b) Tb-Si according to [7]. position of coexisting phases are given in Table 1.…”

The melting diagram of the Ti–Dy–Si system in the Ti–Ti5Si3–Dy5Si3–Dy region

“…The temperature of the last point was estimated as being higher than the liquidus temperature in the alloy 20Ti-50Dy-30Si (1640 • C) and lower than the temperature of quasibinary L Z + Dy 5 Si 3 eutectic (1695 • C). [5] of experimental data [6], refinements [7,8], and (c) Dy-Si [9]. …”

The melting diagram of the Ti–Zr–Sn system below 40at.% Sn

“…The data obtained for as-cast alloys were attributed to the solidus temperatures as it was discussed in ref. [11]. The solidus surface is characterized by the presence of continuous solid solution phases ␤ and 5/3, and ␣ 2 and 2/1 phases, dissolving about 8% and 6% Zr, respectively.…”