铜单晶体在循环形变中形成的形变带

DEFORMATION BANDS FORMED IN CYCLICALLX DEFORMED COPPER SINGLE CRYSTALS

系统研究了循环形变铜单晶体中宏观形变带的产生规律和特征及相应的位错结构，并对其形成机制进行了综合探讨。结果表明，在不同取向铜单晶体的循环形变中，形变带DBI近似沿主滑移面（111）发展，而DBII的惯习面接近传统的扭折面｛101｝，两者成严格的正交分布。这两类形变带的形成可能与循环加载中产生的晶体不可逆旋转密切相关，此外，有利的宏观应力状态也可能导致其它形变带的出现。对于不同取向铜单晶体，形变带可能具有很不相同的位错结构，如PSBs的楼梯结构或迷宫结构等。

The characteristics and corresponding dislocation structures of the deformation bands(DBs), formed in cyclically deformed copper singfe crystals, were summarized systematically. Theformation mechanism of DBs was also explored synthetically. It was shown that the appearance ofDBs seems to be a general phenomenon in difFerently oriented crystals during cyclic deformation. Thedeformation band denoted DBI develops roughly along the primary slip plane (111), and the habit planeof DBll is close to the conventional kink band {101}. Their habit planes are strictly perpendicular toeach other. An analysis based on the crystallographic deformation geometry showed that the localirreversible rotation of crystal which exists during symmetrical push--pull loading may be responsiblefor the formation of DBI and DBll. In addition, a favorable macroscopic state of stress might also beresponsible for the occurrence of other types of DBs. Electron channeling contract in scanning electronmicroscopy (SEM--ECC) observation showed that the DBs, formed in cyclically deformed copper singlecrystals with various orientations, might correspond to quite different dislocation structures, such aspersistent slip bands (PSBs) ladders structure, labyrinth structure and so on.