铝合金大厚板淬火残余应力数值分析

Numerical analysis of residual stresses in quenching of aluminum alloy thick plates

基于淬火会引起铝合金大厚板很大的残余应力,并容易引起淬火变形与裂纹,恶化材料的性能,运用有限元分析软件ANSYS研究了铝合金板材尺寸、淬火介质温度对温度场、应力场和残余应力的影响.基于随温度变化的材料物性参数以及材料表面与淬火介质的换热系数,进行了淬火过程的非线性热传导分析.结果表明,随着板材厚度的增加,铝合金薄板的残余应力增加明显,而铝合金厚板的残余应力未产生太大变化;随着淬火介质温度的升高,厚板的残余应力也无明显降低;对于铝合金厚板,通过优化合金成分等措施来提高合金淬透性,才能有效降低残余内应力,并保证合金的力学性能.

Aluminum alloy thick plates have been widely used as the key material of aircraft structures.Quenching process is one of the most important methods for improving material performance,which introduces a high level of residual stresses and easily lead to distortion and quench cracks,resulting in the performance deterioration.In this paper,the effect of aluminum alloy dimensions and quenching medium temperatures on quenching residual stress was investigated using the finite element program ANSYS.A non-linear heat transfer analysis is carried out by taking into account of the temperature dependence of the thermo-physical properties and transient condition of convection.The results show that for thin aluminum alloy plate,with increasing plate thickness the quenching residual stress increases considerably,while for thick aluminum alloy plate,the quenching residual stress remains almost unchanged.It is believed that improving hardenability of aluminum alloy is the only effective approach for thick aluminum alloy to obtain combination of high mechanical properties and low quenching residual stress after quenching.