纯钛循环变形孪晶的形貌

采用透射电子显微镜学和光学显微镜观察高纯钛单晶及工业纯钛循环变形过程中形成的孪晶，证实了孪晶是纯钛循变形的一种重要方式，几乎在所有位向的拉伸时钛单晶中都有孪生发生，工业纯钛在应变幅低于１．０％下循环变形时孪晶的生成和，在高应变幅高１．５％，随循环变形周次的增加，孪晶分数增加，利用自动图像分析分析仪首次建立了工业纯钛中的形变享晶分数与应变幅，循环周次的定量关系。

OBSERVATION ON CYCLIC DEFORMATION TWINS IN PURE TITANIUM

In this paper,cyclic twins in high purity single titanium crystal and commerical purity titanium were observed with TEM and OM. It is showed that twinning was an important deformation mode.Twinning occured in single titanium crystal with almost all orientations. In commerical purity titanium, at low strain amplitude(less than 1.0%),few deformation twins were observed,however,at high strain amplitude(more than 1.5%),the twin fraction increased with increasing cycles. The quantitative relations among twin fraction, strain amplitude and cyclic number were proposed.