添加Sc对7055铝合金微观结构和力学性能的影响  

Effect of Sc on Microstructure and Mechanical Property of 7055 Al-alloy

作　　者：滕广标 刘崇宇[1] 李剑[2] 马宗义[3] 周文标 向晶[2] 

机构地区：[1]桂林理工大学广西有色金属及特色材料加工教育部重点实验室,桂林541004 [2]广西南南铝加工有限公司,南宁530031 [3]中国科学院金属研究所沈阳材料科学国家(联合)实验室,沈阳110016

出　　处：《材料研究学报》2018年第2期112-118,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51601045);广西重点研发计划(桂科AB16380021);广西八桂学者创新团队项目~~

摘　　要：研究了添加Sc元素对7055铝合金铸造、均匀化处理、轧制和固溶时效过程的微观结构演化以及力学性能的影响。结果表明,向7055溶液中添加质量分数为0.25%的Sc导致在铸造过程中形成初生Al3(Sc,Zr)相。这个相能促使合金发生非均质形核,显著细化合金的铸造组织。在7055-Sc铝合金的均匀化处理过程中析出高密度纳米Al3(Sc,Zr)相,不但能抑制晶粒粗化,而且在后期轧制变形和固溶时效处理过程中还起钉扎晶界、抑制回复与再结晶、保留纤维组织的作用。与7055铝合金相比,7055-Sc铝合金的晶粒尺寸更小,因此具有更有效的细晶强化效应。添加Sc的时效处理态7055铝合金的最大抗拉强度和显微硬度,分别提高到642 MPa和218 HV。The effect of Sc addition on the microstructure and mechanical properties of 7055 Al-alloy as-cast, as well as after homogenization-, rolling-, solution-and aging-treatment was investigated. The addition of 0.25%（mass fraction） Sc could lead to the formation of Al3（Sc, Zr） phase, which can promote the heterogeneous nucleation during casting. Therefore, the microstructure of the as cast 7055 Al-alloy was refined. The precipitation of nano-sized Al3（Sc, Zr） phase occurred during the homogenization treatment of the 7055-Sc Al-alloy, and this nano-sized Al3（ Sc, Zr） phase could effectively inhibit the coarsening of Al grains during homogenization treatment, and play a role in pinning the grain boundaries, therewith inhibiting the recovery and recrystallization, thus retaining the fiber-like structure during subsequent rolling and solution treatments. Compared to the plain 7055 Al-alloy, the 7055-Sc Al alloy exhibited much higher fine grain strengthening effect due to finer grain size and showed higher tensile strength and hardness as high as 642 MPa and 218 HV, respectively.

关 键 词：金属材料 轧制变形 热处理 力学性能 微观组织 铝合金 

分 类 号：TG146.2[一般工业技术—材料科学与工程]