Phase equilibria in the Fe–Sn–Ti system. Part 1: experimental results
摘要
Phase relations in the solidification interval of the Fe–Sn–Ti system and phase equilibria at 1100, 1000 and 500 °C were studied. The results are given as liquidus and solidus projections, the Scheil reaction scheme, isopleths at 5, 20 and 30 at% Sn and partial isothermal sections at 1100, 1000 and 500 °C. It is shown that both full-Heusler TiFe2Sn (τ1) and hexagonal half-Heusler analogue TiFeSn (τ3) phases melt congruently at 1108 and > 1105 °C, respectively, while the Ti2FeSn (τ2), Ti6Fe5Sn9 (τ4) and TiFeSn4 (τ5) phases form by peritectic reactions L + Ti5Sn3 ⇄ τ2, L + τ1 + Ti6Sn5 ⇄ τ4 and L + τ1 + τ4 ⇄ τ5 at > 1155, 645 and 510 °C, respectively. The Heusler TiFe2Sn phase (τ1) has a widest range of homogeneity from 45.6 at% Fe at 25.6 at% Sn to 66.3 at% Fe at 21.0 at% Sn at solidus temperature. The phases Ti6Sn5, Ti5Sn3 and TiFe2 (Laves phase) have extended ranges of homogeneity in the ternary system. A liquid- miscibility gap is well established, which extends noticeably from the Fe–Sn into the ternary system. In total, thirty four-phase invariant reactions were established: two peritectic, seven eutectic and twenty-one transition (U-type).
Graphical abstract