铝合金轮毂失效分析

Failure Analysis of Aluminum Alloy Wheel Hub

某汽车铝合金轮毂在使用一年后发现裂纹,通过断口宏观和微观分析、金相组织分析、化学成分和力学性能检测等。结果表明:轮毂材料因变质不良,组织中残留较多的条块共晶硅和细长针状β相;这种组织缺陷易割裂金属连续性,引起应力集中,降低材料力学性能,特别是塑性显著降低,导致轮毂在安装和使用过程中不能承受内外应力的共同作用而开裂。

The cracks were found in a car＇s aluminum wheel hubs after being used for one year Later. Macro-fractography and micro-fractography, microstructure, chemical analysis and mechanical properties were anal-ed. The results show because of material defect, much lamellar formation of the eutectic mixture and long acicular β phase exist in the microstructure. Such kinds of microstructure easily dissever metal continuity, which cause stress concentration and reduce mechanical properties, especially plasticity. So the wheel hub cracked because it can not bear the stress from inner and outer during installation and use.