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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；＠各复合比下裂端启裂等效应变εf与最大裂端约束R
The deformation behavior and the cracked field of cracked tip of Al single crystal under different loadings of type I + II were investigated by means of in situ tensile test and finite element method. Experimental results show that: (1) the composite crack tip is blunted and sharpened, and the blunt sharpening is controlled by the uniform slip and the concentrated slip, respectively; (2) the composite damage and fracture are the result of uniform slip, and the direction of the crack along the maximum constraint (3) With the increase of H-type component, the COD value of crack initiation increases; (2) the equivalent strain εf and the maximum crack restriction R