添加微量Er、Zr对ZL205A合金组织性能的影响

Effect of adding microscale Er and Zr elements on the Microstructure and Properties of ZL205A Alloy

摘要:

稀土元素对铸造铝合金的组织和性能具有重要的影响。本文通过向ZL205A合金中分别添加0.05%、0.15%和0.25%的Er、Zr元素，研究了不同含量稀土元素在热处理前后对合金微观组织和性能的影响。结果表明，添加微量Er、Zr元素可以有效改善液态合金的流动性，细化晶粒，并促进θ相在晶界交汇处团聚; 当Er、Zr添加量为0.15%时，铸态材料的力学性能较原始合金有大幅度降低，而T5处理后强度达到358Mpa，维氏硬度达到107，延伸率2%，综合性能相对最好；T5处理能够促使合金组织和成分均匀，同时使溶质原子充分扩散，在变形过程中阻碍位错运动和亚晶界的迁移，对延伸率造成不利影响。

Abstract:

Rare earth (RE) elements have important effect on the microstructure and properties of cast aluminum alloys. With addition of 0.05, 0.15 and 0.25 wt% Er and Zr elements to the ZL205A alloy respectively, this article investigated the effect of different content of RE elements on the microstructure and properties of as-cast and T5 heat-treated alloys. The results show that adding micro scale Er and Zr elements can effectively improve the fluidity of liquid alloy, refine the grains and promote the theta phase to concentrate on the intersection of the grain boundaries. When the addition amount is 0.05 wt%, the mechanical properties of as-cast alloy reduced greatly while compared with the initial alloy; after T5 heat-treatment, the tensile strength, Vickers hardness and elongation can respectively reach 358 MPa, 107 and 2%, and the comprehensive performance is the best. T5 heat-treatment can make the microstructure and composition uniform, and also lead solute atoms to diffuse sufficiently, thus hindering the dislocation movement and sub-boundary migration during deformation process, finally taking adverse impact on the elongation.