变形温度对多向锻造7050铝合金组织与力学性能的影响

Effects of deformation temperature on microstructure and mechanical properties of multi-directional forged 7050 aluminum allo

对均匀化后的7050铝合金铸锭进行不同变形温度(390、420、450℃)的多向锻造实验。通过光学显微镜、扫描电镜、电子背散射衍射、透射电镜和室温拉伸性能测试,研究变形温度对锻造态、固溶态和时效态7050铝合金显微组织和力学性能的影响。结果表明:多向锻造对合金中粗大的残余结晶相起到一定的消减效果,残余相的面积分数随变形温度升高而降低。多向锻造后,合金芯部基本为粗大的原始晶粒,随变形温度升高动态再结晶程度增大;固溶处理后,随变形温度升高残余结晶相的面积分数降低,亚晶含量增加;时效处理后,随变形温度升高纳米级析出相的含量增加。时效态合金的强度随变形温度升高而提高,变形温度为450℃时,合金综合力学性能最好,其屈服强度为496.7 MPa,抗拉强度为555.1 MPa,伸长率为8.1%。

Multi-directional forging tests with different deformation temperatures(390,420,450℃)were carried out on homogenized 7050 aluminum alloy ingots.The effects of deformation temperature on the microstructure and mechanical properties of forged,solution-treated,and aged 7050 aluminum alloy were investigated using optical microscope,scanning electron microscope,electron backscattered diffraction,transmission electron microscope,as well as room temperature tensile tests.The results show that multi-directional forging can reduce the amount of residual crystalline phases,the area fraction of residual phases decreases with the increase of deformation temperature.The core of the alloys basically represents as coarse initial grains,the extent of dynamic recrystallization rises with the increase of deformation temperature after multi-directional forging;the area fraction of residual crystalline phases decreases,and the content of sub-grains increases with the increase of deformation temperature after solid-solution treatment;the amount of nanoscale precipitated phase increases with the increase of deformation temperature after aging treatment.The strength of the aged alloy increases with the increase of the deformation temperature.When the deformation temperature is 450℃,the comprehensive mechanical properties of the alloy are the best.The yield strength is 496.7 MPa,the tensile strength is 555.1 MPa,and the elongation is 8.1%.