通过金相组织观察、SEM、硬度测试以及拉伸性能测试等方法,对A356.2低压铸造铝合金车轮内轮缘部位裂纹失效进行分析。分析表明,直接撞击变形初期可能产生微小的裂纹,在长时间行驶中会沿微小的裂纹向内延伸开裂。车轮开裂面及其前面的一定延伸深度的铝基体会不断被氧化,并加速开裂。 The failure of the inner rim of A356.2 low-pressure cast aluminum alloy wheel was analyzed by microstructure observation, SEM, hardness test and tensile test. The analysis shows that there may be tiny cracks in the initial stage of direct impact deformation, and the cracks will extend inward along the tiny cracks during the long-time traveling. The ruptured surface of the wheel and the aluminum substrate with a certain depth of extension in front of it will be continuously oxidized and accelerate the cracking.