Ti－Al－Si三元系中叶α（α_2）／γ相平衡的研究

^^α(α_2)/ PHASE EQUILIBRIA IN Ti-Al-Si SYSTEM

利用电子探针微区成分分析测定了Ｔｉ－Ａｌ－Ｓｉ系低Ｓｉ部分的α（α２）／γ相平衡关系，并进行了热力学分析．结果表明，相对于Ｔｉ－Ａｌ二元系，Ｓｉ的加入使α（α２）／（α（α２）＋γ）相界线向富Ｔｉ方向移动，而（α（α２）＋γ）／γ相界线变化不大；Ｓｉ具有细化片层组织的作用，井使其粗化困难；Ｓｉ在α（α２）相中的溶解度大于γ相，为α相稳定化元素；Ｓｉ含量为１．０％（原子分数）时，组织中出现第三相Ｔｉ５Ｓｉ３．

The partial α(α2)/γ phase equilibria in Ti-Al-Si ternary system at low Si concentration were measured by EPMA and examined with thermodynamic analysis. The results show that the addition of Si in Ti-Al binary system results in the α(α2)/ (α(α2)+γ) phase boundary shifting to Ti-rich side, whereas the (α(α2)+γ/γ) phase boundary shifting little. Si has effect on refining lamellar microstructure and makes the lamellae coarsen difficultly. The Si solubility in α(α2) phase is higher than that in γ phase thereas Si is an αphase-forming element in Ti-Al binary system. A third phase Ti5Si3 appears in the system with Si addition up to 1 .0% (atomic fraction).