航空用7055铝合金微观组织演变及时效处理对性能的影响

Microstructure Evolution and Influence of Aging Treatment on Mechanical Properties of 7055 Aluminum Alloy

对不同时效制度下7055铝合金微观组织演变及强度变化规律进行研究,利用光学显微镜(OM)、透射电镜(TEM)对微观组织进行观察分析,并进行了力学性能测试。结果表明,时效温度为120℃时,屈服强度和抗拉强度均呈现单调增加的趋势,且初期升高速率极快,后续变得平缓,40 h后达到峰值强度;时效温度为160℃时,屈服强度与抗拉强度首先急剧升高,10 h后达到峰值强度,随后均呈现明显的降低趋势;人工时效初期,首先生成与基体完全共格的原子团簇及GP区,随后晶内出现过渡η'相,直至演变为过时效状态下的平衡η相。

Al-Zn-Mg-Cu series 7055 aluminum alloy has high strength, and its microstructure and mechanical properties could be determined by the artificial aging process after solution treatment. The evolution of fine structure and mechanical properties of 7055 aluminum alloy at different artificial aging processes were investigated in this paper. The microstructure was studied by optical metallurgical microscope（OM） and transmission electron microscope（TEM）. The mechanical properties were tested. The results indicate that the yield strength and tensile strength show increasing trend at 120 ℃ ,and the increasing speed was high at first and then became slowly. The peak value of strength reached when holding for 40 h at 120℃, while only needed 10 h at 160℃ and then had a decreasing trend. In microscopic view, the clusters and GP zones formed during the initial aging process,then the metal-stable η＇ formed, and finally the equilibrium η phase retained.