摘要
采用扫描电镜(SEM)、透射电镜(TEM)、拉伸试验机等手段,研究了预变形和时效处理对Al-Mg-Si-Cu合金显微组织和力学性能的影响。结果表明,时效温度为115~175℃时,Al-Mg-Si-Cu合金的硬度会随着轧制变形量的增加而增大;相同变形量下时效温度的升高可以缩短合金到达峰值硬度的时间;经过5%~80%轧制变形后Al-Mg-Si-Cu合金的峰值硬度都相较于传统T6热处理态高。在时效温度为145℃和175℃时,合金的抗拉强度和屈服强度会随着轧制变形量的增加而增大,而断后伸长率在变形量为20%及以上时保持在6%以上,时效温度175℃、变形量为20%时即可获得与传统T6态合金相当的强塑性。Al-Mg-Si-Cu合金在轧制变形过程中会以位错、位错缠结、位错胞和亚晶的过程发生组织结构演变,在变形量为20%及以下时,合金中主要为尺寸较大的β″相、L相和颗粒状第二相;随着变形量增加,第二相尺寸减小并在变形量为80%时形成沿晶面缺陷生长的连续第二相。通过变形+时效处理相结合的方法可以对Al-Mg-Si-Cu合金的强塑性进行调节,从而获得强度和塑性兼备的6000系铝合金。
The effects of pre-deformation and aging on the microstructures and mechanical properties of Al-Mg-Si-Cu alloy were studied by means of scanning electron microscopy(SEM),transmission electron microscopy(TEM)and tensile testing machine.The results show that the hardness of the Al-Mg-Si-Cu alloy increases with the increase of rolling deformation at the aging temperature of 115-175℃;the increase of aging temperature at the same deformation amount can shorten the time for the alloy to reach its peak hardness;The peak hardness of the Al-Mg-Si-Cu alloy after rolling deformation of 5%-80%is higher than that of the traditional T6 heat treatment state when the aging temperature is 145℃and 175℃.The tensile strength and yield strength of the Al-Mg-Si-Cu alloy increase with the increase of rolling deformation at 145℃and 175℃,while the elongation after fracture remains above 6%when the deformation is 20%or more.The strength and plasticity of the alloy can be comparable to that of the traditional T6 alloy at the condition of 175℃with 20%deformation.During rolling deformation,the structural evolution in the Al-Mg-Si-Cu alloy occurs in the process of dislocation,dislocation entanglement,dislocation cells and subgrains;when the deformation is 20%or less,the major phases in the Al-Mg-Si-Cu alloy are large-sizedβ″,L phase and granular secondary phase.With the increase of deformation,the size of the secondary phase decreases,and a continuous secondary phase grows along the crystal plane defect when the amount of deformation is 80%.The strength and plasticity of the Al-Mg-Si-Cu alloy can be adjusted by combining deformation with aging treatment,and the 6000 series aluminum alloy with both strength and plasticity can be obtained.
作者
许峰
胡可
罗凤翔
Xu Feng;Hu Ke;Luo Fengxiang(Aviation College,Pingdingshan Industrial College of Technology,Pingdingshan Henan 467000,China;Mechanical and Electrical Engineering,Central South University,Changsha Hunan 410083,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第9期140-146,共7页
Heat Treatment of Metals
基金
国家自然科学基金(51274245,51571083)
河南省教育厅自然科学研究计划(2009C480001)
