固溶处理对7A09超高强铝合金组织与拉伸性能的影响

Effects of Solution Treatment on Microstructure and Tensile Properties of 7A09 Ultra High Strength Aluminum Alloy

采用扫描电子显微镜、X射线衍射仪、拉伸试验等研究了不同时间固溶对7A09铝合金显微组织及拉伸性能的影响。结果表明:对铸态7A09铝合金进行475℃不同时间的固溶,再进行120℃×16h的时效处理,随着固溶时间的增加,7A09铝合金的抗拉强度与伸长率先升高后降低,固溶80 min 7A09铝合金的抗拉强度与伸长率均达到最大值,分别为567 MPa和8.2%。铸态7A09铝合金晶界处有明显连续分布的MgZn_(2)相,随着固溶时间的增加,MgZn_(2)相越来越多溶入基体。7A09铝合金经过475℃×80min固溶处理后,MgZn_(2)相基本溶入基体,固溶效果最佳。

The effects of solution treatment at different time on the microstructure and tensile properties of 7A09 aluminum alloy were studied by scanning electron microscope,X-ray diffraction and tensile test.The results show that the tensile strength and elongation of as cast 7A09 aluminum alloy increase firstly and then decrease with the increase of solution time after solution treatment at 475℃for different time and aging treatment at 120℃for 16 h.The tensile strength and elongation of 7A09 aluminum alloy reach the maximum value of 567 MPa and 8.2%respectively after solution treatment for 80 min.There is continuous MgZn_(2) phase at the grain boundary of as-cast 7A09 aluminum alloy.With the increase of solution time,more and more MgZn_(2) phases dissolve into the matrix.After solution treatment at 475℃for 80 min,the MgZn_(2) phase of 7A09 aluminum alloy basically dissolves into the matrix,and the solution effect is best.