压铸ADC12铝合金基座的开裂机制分析

Cracking Mechanism of ADC12 Die Casting Aluminum Alloy Pedestal

利用扫描电镜、金相显微镜、电感耦合等离子发射光谱仪等手段,对压铸ADC12铝合金云台基座开裂失效进行组织及成分分析,并借助弹塑性有限元法分析了云台基座在使用过程中采取急停等操作后的应力分布情况。结果表明,ADC12铝合金在铸造过程中产生大量的缩孔、偏析等缺陷,特别是在弯角部位,存在偏析瘤。这些缺陷,导致合金的力学性能严重下降。此外,在基座底部前后端与高台的交界处存在应力集中。因此,导致压铸ADC12铝合金云台基座的开裂失效。

By using OM,SEM,ICP analysis,microstructure and phase composition of ADC12 die casting aluminum alloy were investigated,and the stress distribution of the pedestal during scram operation of the robot was analyzed by using FEM simulation.The results reveal that lots of defects are generated in the structure of ADC12 die casting aluminum alloy during casting process,such as shrinkage cavity,segregation and segregation tumors,especially in the bend area.The mechanical properties of the alloy are decreased seriously due to the microstructure defect.In addition,there exists a stress concentration at the junction between the front and rear of the base and the platform.Therefore,the comprehensive influence of the casting defects and stress concentration during scram operation results in cracking failure of the ADC12 die casting aluminum alloy pedestal.