变形及热处理对Al-Sc二元合金力学性能与导电性能的影响

研究了Al-x Sc(x=0、0.10%、0.45%、0.70%)合金在挤压变形、拉拔变形和热处理过程中的力学性能和导电性能的变化。结果表明,铸态Al-Sc二元合金的强度都随Sc含量的增加而增加,而电导率逐渐降低。挤压变形后,Al-Sc合金的晶粒均有所细化,屈服和抗拉强度大幅提升,塑性略有下降;拉拔变形后,加工硬化使各Al-Sc合金的强度进一步提高,伸长率大幅降至1%左右;经过400℃保温2 min+300℃保温150 min的热处理后,Al-Sc合金的伸长率大幅提升,纯铝和Al-0.1%Sc合金的强度降低,然而添加0.45%和0.70%Sc的合金强度却有所升高,这主要是由于热处理后含Sc第二相析出导致的。两种变形过程对Al-Sc合金电导率的影响很小,热处理可通过分解铝钪固溶体大幅提高Al-Sc合金的电导率。最终制备的Al-0.45%Sc合金屈服强度,伸长率和电导率分别为210 MPa,7.2%,34.8×10^6S/m,兼具良好的力学性能和导电性能。

Effect of Deformation and Heat Treatment on Mechanical and Electrical Properties of Al-Sc Binary Alloy

The mechanical properties and electrical conductivity of Al-x Sc(x=0,0.1,0.45,0.7 wt.%)alloy during extrusion deformation,drawing deformation and heat treatment were investigated.The results show that with increase of Sc content,the strength of as-casting Al-Sc binary alloy increases while the conductivity decreases.After extrusion deformation,the grains are refined and the strength of Al-Sc alloy is greatly improved,also the plasticity decreased slightly.Due to the effect of work hardening,the strength of as-drawn alloys are further increased and the elongation decreases to about 1%.After heat treatment at 400℃for 2 min and at 300℃for 150 min,the elongation of Al-Sc alloy is greatly improved.In addition,the strength of pure Al and Al-0.1%Sc alloy decrease,but strength of Al-0.45%Sc and Al-0.7%Sc alloy increase,which is mainly due to the precipitation of the second phase contained Sc after heat treatment.The two deformation processes have little influence on the conductivity of Al-Sc alloys.Heat treatment can greatly improve conductivity of Al-Sc alloys by decomposition of solid solution.Finally,the yield strength,elongation and conductivity of Al-0.45%Sc alloy prepared are 210 MPa,7.2%and 34.8×10^6 S/m,respectively,which has good mechanical properties and electrical conductivity properties.