Sc对7050铝合金力学性能和再结晶行为的影响

Effects of Scandium on the Mechanical Properties and Recrystallization Behaviour of 7050 Aluminum Alloy

制备了4种Sc含量的7050合金,对比研究了Sc含量对7050合金微观组织、力学性能及再结晶行为的影响。结果表明,Sc对7050合金的铸态组织有很强的细化作用。随着Sc含量的增加,合金晶粒由粗大的树枝晶逐渐转变为细小的等轴晶;向7050合金中添加少量的Sc,可在合金塑性不降低的情况下,使合金的抗拉强度明显提高,并在Sc含量为0.26%时,合金具有最佳的力学性能,但加入更多Sc对合金力学性能的进一步提高没有明显作用;与不含Sc的7050合金相比,Sc含量为0.26%时的7050合金的再结晶温度明显上升,加Sc可使合金的起始再结晶温度提高到480℃以上。

Four types of 7050 aluminum alloys with different scandium addition were prepared,and effects of scandium on the microstructure,mechanical properties and recrystallization behaviour of 7050 alloy were investigated.The results show that scandium has a remarkable refining effect on the microstructure of as-cast 7050 alloy,and the grains in the alloy are transformed to fine equiaxed grain from coarse dendrite with increasing in scandium content.The tensile properties of the alloy are obviously enhanced with absence of decreasing the plaseticity of the alloy by adding a small amount of scandium to7050 alloy,and the best tensile properties can be obtained with the scandium content of 0.26%.However,it has no obvious effect on the mechanical properties of the alloy by adding more scandium to 7050 alloy.Compared with that of the 7050 alloy without addition of scandium,the recrystallization temperature of the 7050 alloy with the scandium content of 0.26%rises,and the starting recrystallization temperature of the alloy is raised to above 480 ℃.