影响TiAl合金塑性的电子结构因素

应用ＥＨＴ紧束缚能带计算方法， 系统研究了Ｔｉ－４８Ａｌ－２Ｍ 为模型的γ－ＴｉＡｌ掺杂合金的电子结构。发现能有效地改善合金塑性的元素Ｖ、Ｃｒ、Ｍｎ 主要在两方面改变了γ－ＴｉＡｌ合金的电子结构，即改善Ｔｉ周围成键强度的各向均衡性和改变Ｔｉ、Ａｌ参与成键的电子分布，使成键电子云的球形化成分增大。研究结果表明Ｖ、Ｃｒ、Ｍｎ 等取代Ａｌ时成键的均衡性及电子云球形化均增大，从而有利于材料变形改善塑性，而加入Ｆｅ、Ｃｏ、Ｎｉ虽然改善电子云的球形化但却不利于成键强度的均衡性，因而对合金的塑性无明显改善。

Electronic Structure Factors Affecting the Ductility of TiAl Alloy

The electronic structures of γ TiAl modeled by Ti 48Al 2M have been studied using the tight binding method(EHT). The alloying elements, V, Cr and Mn, which are profitable to improve ductility of γ TiAl, affecting alloy electronic structure mainly in two aspects. One is to make bonds strong average around Ti, the other is to make the bonding electronic cloud of Ti and Al more spherically symmetrical. The result shows that doping V, Cr amd Mn substitute Al in \$γ\$ TiAl may have the same effect in the bond changing and electronic distributing, so profit to materials shape changable. However, doping Fe, Co and Ni may make the electronic cloud become symmetrical, but make big difference to bond strength around Ti, so it is not effective to improve the ductility.