【摘要】 本文用经验电子理论的键距差方法对金属间化合物TiAl的共价电子数n_c、晶格电子数n₁以及共价电子数与总价电子数之此η进行了计算。结果表明:晶体的形成热和脆性等与n_c,n₁或η密切相关。η值越大,晶体的强度越高,也越脆。这样便可说明为什么TiAl化合物很脆,根本不能冷形变。还表明,通过热处理等手段降低TiAl金属化合物的有序度,适量加入某些使轴比c/a增加的第三种元素可使TiAl韧性得到改善。更多还原

【Abstract】 The parameters of intermetaliic compound TiAl, such as the number of covalent valence electron (nc), the number of lattice valence electron (n_l) and the ratio of Nc to the number of total valence electron (η) are calculated by BLD (bond length difference) method of empirical electron theory. The result shows that the heat of formation and brittleness of crystal are in close relationship with parameters Nc, n_l or η, and that the higher the value of η, the higher the strength and brittleness of crystal. Thus it may be illustrated that the toughness of TiAl is so poor that it could not be cold deformed at all. This paper indicates that the toughness of TiAl will be increased by heat treatment in order to decrease the degree of order of crystal or by adding some third element to increase the axial ratio c/a.更多还原