共轭双滑移取向铜单晶疲劳位错结构的SEM-ECC观察

利用扫描电镜电子通道衬度(SEM-ECC)技术观察和分析了■ 2 3]和■ 1 2]共轭双滑移取向铜单晶体的循环饱和位错结构.结果表明,驻留滑移带(PSBs)的位错结构随晶体取向的不同可呈现出不同的形态,如:■ 1 2]晶体中的楼梯结构和■ 2 3]晶体中的沿主滑移面排列的不规则或较规则胞结构.同时还观察到■ 2 3]晶体中形变带的位错结构由一些不规则的墙和胞结构组成.对于晶体取向位于标准取向三角形0 0 1]-■ 1 1]边上的铜单晶体,其疲劳位错结构随晶体取向的不同发生有规律的变化,即:当晶体取向从■ 1 2]分别向■ 1 1]和0 0 1]移动时,位错结构由PSB楼梯...

SEM-ECC Observations of Dislocation Structures in Fatigued Copper Single Crystals Oriented for Conjugate Double Slip

The dislocation structures in cyclically saturated copper single crystals oriented towards 2¯23] and 1¯12] conjugate double slip were observed and analyzed using electron-channelling contrast technique in scanning electron microscopy (SEM-ECC). It was found that the persistent slip bands (PSBs) might exhibit different dislocation features depending upon crystallographic orientation, such as ladder structures in the 1¯12] crystal and irregular or partially regular cell structures aligned along the primary slip plane in the 2¯23] crystal. Moreover, the dislocation microstructures in deformation bands (DBs) formed in the 2¯23] crystal were observed comprising irregular dislocation walls and cells. For the crystals located on the 001]-1¯11] side of the standard stereographic triangle, the dislocation structures change regularly with the variation in crystallographic orientation. When the orientation varies from the 1¯12] orientation to 1¯11] or 001], the dislocation structures would evolve from PSB ladders as cells or labyrinths.