Classification of γ-γ and γ-α2 lamellar boundaries on the basis of continuity of strains and slip-twinning planes in fatigued TiAl polysynthetically twinned crystals
Classification of γ-γ and γ-α2 lamellar boundaries on the basis of continuity of strains and slip-twinning planes in fatigued TiAl polysynthetically twinned crystals
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基于疲劳 TiAl 多合成孪生晶体中应变和滑移孪晶面连续性的 γ-γ 和 γ-α2 层状边界分类
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Y. Umakoshi
中科院分区：
文献类型：
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作者：
T. Nakano;H. Biermann;M. Riemer;H. Mughrabi;Y. Nakai;Y. Umakoshi
本文从几何和实验两方面研究了TiAl（γ）-Ti 3Al（α2）两相合金中片层晶界对变形的影响，并根据宏观应变分量的连续性和滑移孪晶面对片层晶界的类型进行了分类。TiAl多晶孪晶在420 MPa下进行疲劳试验，加载轴平行于片层边界，γ畴为（112）畴。片层晶界分为13组，包括3组γ-γ真孪晶、3组γ-γ假孪晶、3组γ-γ 120°旋转晶界和4组γ-α2界面。它们被进一步细分为具有连续几何形状和不连续几何形状的两组。透射电子显微镜观察表明，在某些γ畴中激活了Schmid因子所未考虑到的变形模式，以维持通过片层边界的宏观应变连续性，片层边界是变形传递的有效屏障。
Abstract Effects of lamellar boundaries on deformation in two-phase TiAl(γ)-Ti3AI(α2) alloy were geometrically and experimentally examined and the types of the boundaries were classified focusing on the continuity of macroscopic strain components and slip-twinning planes. TiAl polysynthetically twinned crystals were fatigued at 420 MPa with the loading axis parallel to the lamellar boundaries and (112) in γ domains. The lamellar boundaries were classified into 13 groups composed of three γ-γ true-twin, three γ-γ pseudotwin, three γ-γ 120° rotation boundaries and four γ-α2 interfaces. They were further subdivided into two groups with continuous and discontinuous geometry. Transmission electron microscopy observations showed that deformation modes unexpected from Schmid factor consideration were activated in some γ domains to maintain the macroscopic strain continuity through the lamellar boundary and that the boundary acted as an effective barrier to the transfer of deformation.