双滑移取向Cu单晶的循环形变行为──Ⅱ．滑移带和形变带

CYCLIC DEFORMATION BEHAVIOUR OF Cu SINGLE CRYSTALS ORIENTED FORDOUBLE SLIP Ⅱ. Persistent Slip Bands and Deformation Bands

用光学显微镜和扫描电镜研究了双滑移取向（［０３４］，［１１７］）Ｃｕ单晶循环饱和后的表面形貌，塑性分切应变幅（γｐｌ）低于１０^（－３）时，［０３４］晶体表面上要为主滑移系的驻留滑移带（ＰＳＢｓ）占据，次滑移只在边缘区域启动，其ＰＳＢｓ细窄（＜１μｍ），体积百分数在１％以下．γｐｌ＞１０^（－３）时，次滑移开始在试样的中部启动，同时，表面出现二种贯穿晶体的宏观形变带（ＤＢＩ，ＤＢＩＩ），滑移带在形变带内集中．［１１７］晶体在γｐｌ＝４．４×１０^（－４）时，双滑移现象已十分明显．γｐｌ＞１０^（－３）时，表面也形成与前者相似的形变带．ＤＢＩ的惯习面与主滑移面平行（［０３４］晶体）或接近（［１１７］晶体），ＤＢＩＩ的惯习面则与前者垂直，文章讨论了形变带形成的可能原因．

The surface morphologies of fatigued Cu single crystals with double slip orientations ([034], [117]) were investigated by optical and scanning electron microscopy. At plastic shear strain amplitude (γpl) below 10￣(-3), the surface of [034] crystal is mainly covered by the persistent slip bands(PSBs) of primary slip, and the secondary PSBs only appear at the edge regions of the specimens with a volume fraction less than 1 percent. At γpl> 10￣(-3), the secondary slip system becomes active on a large scale, particularly at region between primary PSBs, and two kinds of macro deformation bands (DBⅠ, DBⅡ) form with primary PSBs concentrated inside. [117] crystal shows a pronounced double slip phenomenon even at γpl～4.4 × 10￣(-4). At γpl > 10￣(-3), deformation bands also form similar to those of [034] crystal. The habit plane of DB Ⅰ is either parallel to (in [034] case) or near to (in [117] case) primary slip plane, while that of DBⅡ is perpendicular to the former one.The possible reason of the formation of deformation bands is discussed.