【摘要】 研究了经等径角挤压工艺(ECAP)制备的超细晶和粗晶Cu-0.6Cr合金的疲劳裂纹的产生和断裂,用扫描电镜观察表面和断口形貌。研究发现,粗晶Cu-0.6Cr合金的驻留滑移带非常杂乱,超细晶铜铬合金的剪切带沿着ECAP最后一道次剪切面发展,沿着ECAP最后一道次剪切面发展的剪切带在疲劳断裂初期和早期的裂纹增殖中起着决定性作用。ECAP挤压形变剪切面和沿平面界面的晶界剪切滑动是循环形变剪切带形成的主要机制。粗晶铜铬合金的断口呈塑性特征,而超细晶铜铬合金的断口则显示脆性特征。更多还原

【Abstract】 The producing of fatigue cracks and fracture in the ultrafine-grained(UFG) and coarse grained(CG) Cu-0.6Cr copper alloy prepared by equal channel angular pressing were studied.The surface and fracture surface images of UFG and CG were observed by means of scanning electron microscopy.The results show that the persistent slip bands of CG Cu-0.6Cr copper alloy is mixed up,the shear bands of UFG Cu-0.6Cr copper alloy developing along the shear planes of the last ECAP process are decisive for fatigue crack initiation and early crack propagation.The share plane of extrusion deformation and the slipping along the grain boundary of plane interface is the mostly forming mechanism of shear bands during cyclic deformation.The fracture of CG Cu-0.6Cr copper alloy is plastic fracture,but the fracture of the UFG Cu-0.6Cr copper alloy shows the brittle properties.更多还原