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.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
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~~
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
metallic materials, rolling, heat treatments, mechanical properties, microstructure, AI alloys
