Mg-Y合金中共轴{1121}孪晶交互的电子显微研究

TEM study of the co-zone{1121}twinning interaction in Mg-Y alloy

本文通过TEM观察,在室温轧制的Mg-10Y(wt.%)合金中发现了共轴{1121}孪晶变体交互现象。通过模型构建和Schmid因子分析,对交互位置孪晶不对称生长导致的台阶结构给出了解释。当这种共轴孪晶变体发生交互作用时,在相互作用位置,一个{1121}孪生变体的生长会在另一个孪生变体的两侧引起不同的应力集中,在两孪晶所夹锐角侧,孪晶生长表现出相互促进作用,而在钝角侧则表现为相互抑制,这使得孪晶发生不对称生长,形成阶梯结构。通过衍射分析,确认孪晶交互界面为靠近基体(1120)平面的低角度倾斜边界,确定(1120)面为此类孪晶交互接触面的惯习面,推断交互面以(1122)T1//(1122)T2的形式存在.

In this paper,a typical co-zone{1121}twin-twin junction was found by TEM in Mg-10Y(wt.%)alloy,which is rolled at room temperature.Schmidt factor analyzing and{1121}twin modeling were applied to explain the presence of step at the interactive position,which is caused by the asymmetric twin growth in the interaction configuration.It has been clarified that the stress concentration resulted from the twin-twin interaction can have significantly different effects on the growth of{1121}twin variants in the interaction configuration depending on twinning direction.Based on diffraction simulation,the twin-twin junction boundary has been identified to be a definite planar boundary whose ideal crystallographic habit plane should be identical to the(1120)plane of matrix.