TWINNING MODES IN LATTICES
TWINNING MODES IN LATTICES
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DOI：
10.1098/rspa.1969.0208
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发表时间：
1969-01-01
影响因子：
--
通讯作者：
CROCKER, AG
中科院分区：
文献类型：
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作者：
BEVIS, M;CROCKER, AG
形变孪生是晶体材料塑性变形的重要影响因素。与变形孪生相关的宏观形状变形是一种简单剪切，本文将早期论文(Bevis&Crocker 1968)中发展的广义孪生剪切理论应用于特定晶格，并描述了由此产生的孪生模式。对于立方晶格的特殊情况，我们首先研究了所有七种不同类型的孪生模式的例子，其中五种不满足变形孪生的经典取向关系。然后研究了由单位对应矩阵的变体产生的七个晶系中的模之间的关系。这些模式在性质上都是常规的，但是，当对更复杂的对应矩阵重复该过程时，得到的大多数模式都是非常规的，具有四个无理孪生元素。详细讨论了与其中几种模式相关的取向关系。虽然所给出的模式是为了说明理论的相关特征而特别选择的，但其中许多模式被证明是金属和其他晶体材料中的工作形变孪生模式。最后讨论了理论中孪生剪力形式分解成的分量对应和旋转矩阵的物理意义，并简要讨论了分析的扩展，从而使晶格中的相变剪力得以研究。
Deformation twinning is an important contributory factor in the plastic deformation of crystalline materials. The macroscopic shape deformation associated with deformation twinning is a simple shear, and in this paper the generalized theory of twinning shears developed in an earlier paper (Bevis & Crocker 1968), is applied to specific lattices and the resulting twinning modes described. Examples of all seven different classes of twinning mode, five of which do not satisfy the classical orientation relations of deformation twinning are first examined for the special case of cubic lattices. Relations between modes in the seven crystal systems which arise from variants of the unit correspondence matrix are then investigated. These modes are all conventional in character, but, when this procedure is repeated for a more complex correspondence matrix, most of the resulting modes are non-conventional, having four irrational twinning elements. The orientation relations associated with several of these modes are discussed in detail. Although the modes presented have been chosen specifically to illustrate pertinent features of the theory, many of them are shown to be the operative deformation twinning modes in metals and other crystalline materials. Finally the physical significance of the component correspondence and rotation matrices, into which a twinning shear is formally resolved in the theory, is discussed and extensions of the analysis, which enable transformation shears in lattices to be studied, are briefly considered.