Mechanistic modeling of deformation and fracture behavior in TiAl and Ti3Al
Mechanistic modeling of deformation and fracture behavior in TiAl and Ti3Al
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DOI：
10.1016/0921-5093(94)03206-8
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发表时间：
1995-02
期刊：
影响因子：
6.4
通讯作者：
M. Yoo;J. Zou;C. Fu
中科院分区：
文献类型：
--
作者：
M. Yoo;J. Zou;C. Fu
基于第一性原理局域密度泛函方法研究了TiAl和Ti 3Al的相稳定性和体相性质，并采用线弹性理论分析了两相层状γ-TiAl合金的变形和断裂行为。在计算的弹性常数方面，杨氏模量和剪切模量在Ti 3Al中比在TiAl中高。弹性不相容的耦合效应降低了界面处的错配应变，位错堆积引起的应力集中的模态混合度对界面处是否发生滑移转移或微裂纹起着重要作用。用（112）[110]裂纹与α2-Ti 3Al板的弹性相互作用解释了多晶孪晶缺口断裂的形貌。讨论了影响TiAl脆韧转变行为的其它因素。
Phase stability and bulk properties of TiAl and Ti3Al are investigated based on the first-principles local-density-functional approach, and deformation and fracture behavior of two-phase lamellar γ-TiAl alloys are analyzed using the linear elasticity theory applied to interfaces, dislocations, and cracks. In terms of the calculated elastic constants, Young's and shear moduli are higher in Ti3Al than in TiAl. The coupling effect due to elastic incompatibility reduces the misfit strain at an interface when a tensile stress is applied normal to it. The mode mixity of stress concentration by a dislocation pile-up plays an important role in determining whether slip transfer or microcracking occurs at the interface. The fracture morphology reported in notched polysynthetically twinned crystals is explained in terms of the elastic interaction of a (112 )[11 0] crack with an α2-Ti3Al plate. Additional factors that are involved in the brittle-to-ductile transition behavior of TiAl are discussed.