Al-Ti-B细化剂对半连续铸造7050铝合金组织及性能的影响

Effects of Al-Ti-B Refiners on Microstructure and Properties of Semi-continuous Casting 7050 Aluminum alloy

分析了Al-5Ti-0.2B、Al-5Ti-1B和Al-3Ti-1B等3种晶粒细化剂的微观组织差异,研究了3种细化剂对大尺寸7050铝合金晶粒的细化效果及对7050-T7541态厚板性能的影响。结果显示,3种细化剂中TiAl3相主要呈块状分布,尺寸为15~50μm,TiB2相呈小颗粒状,且易偏聚,尺寸为1~2μm。3种细化剂中TiAl3相含量分别为8.16%、5.60%和1.45%,从细化效果来看,Al-5Ti-1B细化效果最佳,铸锭芯部和边部尺寸分别为87μm和60μm。同时,添加Al-5Ti-1B细化剂的7050铝合金厚板的力学性能最佳,抗拉强度、屈服强度及伸长率分别为555 MPa、505 MPa和14.8%。

The difference in microstructure of Al-5 Ti-0.2 B,Al-5 Ti-1 B and Al-3 Ti-1 B grain refiners, and the effects of the three refiners on the grain refinement of large-sized 7050 aluminum alloy and the properties of 7050-T7451 state thick plate were investigated. The results reveal that TiAl3 phase in three refiners is mainly distributed as a block with a size of 15~50 μm, while TiB2 phase is a small particle with a size of 1~2 μm and easy to aggregate irregularly. The TiAl3 phase content in the three refiners is 8.16%, 5.60% and 1.45%, respectively. The refining effect of Al-5 Ti-1 B refiner is the desirable, with the core size of 87 μm and edge size of 60 μm.Meanwhile, the 7050 alloy thick plate with Al-5 Ti-1 B refiner has the satisfied mechanical properties, and the tensile strength, yield strength and elongation reach up to 555 MPa, 505 MPa and 14.8%, respectively.