Ⅰ+Ⅱ载荷下Al单晶裂纹尖端形变和损伤行为的SEM原位分析  

SEM ANALYSIS OF DEFORMATION AND DAMAGE AT CRACK TIP OF Al SINGLE CRYSTAL UNDER MIXED Ⅰ+Ⅱ MODE LOADING

作　　者：沙江波[1] 邓增杰[2] 周惠久[2] 

机构地区：[1]广东工业大学材料科学工程系,广州市510090 [2]西安交通大学

出　　处：《材料研究学报》1997年第1期25-30,共6页Chinese Journal of Materials Research

基　　金：国家教委博士点基金

摘　　要：应用扫描电镜原位拉伸的方法和有限元法研究了Al单晶在不同Ⅰ＋Ⅱ型复合载荷下裂纹尖端变形损伤行为和裂端的变形场、约束场．实验结果表明：①复合裂端变形是钝一锐化模型，钝锐化分别由均匀滑移和集中滑移控制；②复合损伤及断裂是均匀滑移的结果，裂纹沿裂端最大约束的方向扩张；③随H型分量的增加，裂纹启裂的COD值增加；An in-situ tensile experiment in a SEM and finite element method have been made into the deformation and damage behaviors, the strain and restrain fields at the crack tip under the different Ⅰ+Ⅱmixed mode ratios in an Al single crystal.The results show that (l)the deformation at the crack tip likely to beof type of blunting-sharpening under the mixed loading,which are controlled by uniformed and localized slips respectively;(2)The mixed damage is controlled by uniformed slip,the fracture is characterized by dimple,the propagating of marco-crack is proposed to be along the direction of the maximum restrain;(3)The COD values for initiation increase with an increasing of the mode Ⅱ component;(4)The effective strain f and maximum restrain level R. for initiation under different Ⅰ+Ⅱ mixed ratios satisfy the fexp[(3 / 2)' R ] = 6.12 equation, by which the ductile damage can be described.

关 键 词：复合型 原位观察 有限元 裂纹 损伤 铝单晶 

分 类 号：TG146.21[一般工业技术—材料科学与工程] O346.1[金属学及工艺—金属材料]