5A01高镁铝合金的PLC效应及其力学性能

Portevin-Le Chatelier Effect and Mechanical Properties of 5A01 Aluminum Alloy

采用DSC、金相组织观察、透射电子显微镜及室温拉伸实验研究了5A01(6.13wt%Mg)高镁铝合金的组织、锯齿屈服(PLC)效应及不同应变速率下的力学性能。结果表明:淬火态、150℃/1h时效和350℃/1h时效三种状态合金中均分布有β相,但以150℃/1h时效态合金中的β相数量最多;在150℃时效,随时效时间(1～72h)的延长,合金的PLC效应减弱;在时效时间为1h时,随时效温度150℃升高到350℃,合金的PLC效应增强;在应变速率为6.66×10-4s-1时,淬火态、150℃/1h及350℃/1h时效态合金的极限抗拉强度和延伸率变化不大,在应变速率为8×10-5s-1时,150℃/1h时效态合金的极限抗拉强度最高,延伸率最低;5A01铝合金的PLC效应及不同应变速率下力学性能变化的机理,可利用固溶Mg原子和位错相互作用理论进行合理解释。

Differential scanning calorimetry（DSC）,microstructure observation,tensile test at room temperature and transmission electron microscopy（TEM） were used to study the microstructure,Portevin-Le Chatelier（PLC） effect and mechanical properties under different strain rates for 5A01（6.13wt%Mg） aluminum alloy.The results show that β-phase precipitated out from the as-quenched alloy,the alloy aged at 150℃ or at 350℃ for 1h,in which the amount of β-phase in the alloy aged at 150 ℃ for 1h is the highest.And with increasing the aging time（1-72h）,the PLC effect of the alloy aged at 150 ℃ is weakened.With increasing the aging temperature from 150℃ to 350℃,the PLC effect of the alloy aged for 1h is strengthened.In addition,when the strain rate is 6.66×10～（-4）s～（-1）,ultimate tensile strength（UTS） and elongation strain of the tested samples do not have obvious change;but when the strain rate is down to 8×10～（-5）s～（-1）,UTS and elongation strain of the alloy aged at 150℃/1h are the highest and the lowest,respectively.The mechanism of PLC effect and changes of mechanical properties for 5A01 aluminum alloy can be explained by the interaction between Mg atoms and dislocations.