中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 17 Special 1 November 2007 |
（1. Center of High Resolution Electron Microscopy, College of Materials Science and Engineering,
Hunan University, Changsha 410082, China;
2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China）
Abstract:In-situ straining experiments in transmission electron microscopy were performed to investigate the propagation of crack, twinning and interaction of crack with twins. Lots of micro-twins were observed in the deformation band near the tip of crack. The stress is relaxed by the formation of micro-twins and the densely developed micro-twins prevent the growth of crack from the deformation band, subsequently the cracks extend into adjacent grains across grain boundaries, and grow along cleavage plane. Multiple twins are observed in hot-rolling AZ31 magnesium alloys, when cracks propagate into twins through twin grain boundaries(GBs), the direction of growth deviates. It is concluded that twins, especially multiple twins effectively baffle the development of crack.
Key words: multiple twins; in-situ TEM experiments; crack; AZ31 Mg alloys
