【摘要】 采用分离式Hopkinson压杆装置(SHPB)和扫描电镜电子通道衬度(SEM-ECC)技术研究了不同取向疲劳态铜单晶高应变率压缩下形成的绝热剪切带(ASB)．实验表明, ASB形成的临界应变与晶体取向有关,接近压缩临界双滑移取向晶体需要的临界应变最小,单滑移和压缩共轭双滑移取向的次之,共面双滑移取向的最大．本实验条件下形成的ASB内部典型的位错组态为位错胞结构,未观察到再结晶现象．根据空间位向, ASB可以分为3类:第1类非常接近铜晶体疲劳时形成的第2类形变带(DBII)平面,其临界应变最小;第2类ASB位向或者比较接近DBII平面或者比较接近第1类形变带(DBI)平面, 其临界应变居中;第3类ASB位向与DBI和DBII平面均不接近,其临界应变最大．更多还原

【Abstract】 Adiabatic shear bands (ASBs) were studied by SEM electron channeling contrast (ECC) technique, which formed in fatigued copper single crystals with different orientations under high velocity impact using split-Hopkinson pressure bar (SHPB). The experimental results show that the critical strain of ASBs’ formation is orientation-dependent. Single crystal close to the compression critical double slip orientation needs less strain for ASB formation than the crystals with typically single slip and close to compression conjugate double slip orientations. Single crystal close to the coplanar double slip orientation needs the maximum critical strain. Under current experimental circumstance the typical dislocation pattern within ASBs is dislocation cell structure, and no recrystallization was observed. There are three types of ASBs according to their orientations. The first type is that the plane of ASB is very close to the habit plane of the second type deformation band (DBII) in fatigued copper single crystals, which needs the minimum critical strain to form. The second type is rather close to the habit plane of either DBI (the first type deformation band) or DBII, which needs a modest critical strain. The third type is neither close to the habit plane of DBI nor DBII, which needs a the maximum critical stain.更多还原