ADC14铝合金变速轮组合肋条早期断裂失效分析

采用化学成分分析、扫描电镜断口观察、金相检验等方法对某公司ADC14铝合金变速轮组合肋条的早期断裂原因进行了分析。结果表明，大量不均匀分布的粗大块状初晶硅、沿晶分布的块状脆性相、针状的脆性铁相以及较多的疏松铸造缺陷，严重割裂基体，使肋条的塑性降低、脆性增大，导致肋条产生早期脆性断裂。在此分析的基础上提出了铸造工艺的改进措施。

Failure analysis of early fracture of the combination rib in a change wheel of ADC14 aluminium alloy

We analyzed early fracture cause for the combination rib in a change wheel of ADC14 aluminium alloy with chemical composition analysis,SEM observation and metallographic examination.Results show that inhomogeneous distribution of thick massive primary silicon,intergranular distribution of massive brittle phase,acicular brittle iron phase and more casting defects of porosities in the matrix can make the plasticity reduction and the brittleness increase,and further cause early brittle fracture of the rib.We therefore present the improved methods for casting technique.