拉拔变形量对Al-Mg-Si合金线微观组织和强度的影响

Effect of drawing deformation on microstructure and strength of Al-Mg-Si alloy wire

研究了Al-Mg-Si合金线的强度和微观组织结构与拉拔变形量的关系,分析了Al-Mg-Si合金线的强化机制。结果表明:Al-Mg-Si合金线强度随变形量的增大呈现两阶段特征,第一阶段为变形量小于55.3%时,Al-Mg-Si合金线强度随着变形量的增大而缓慢增加,第二阶段为变形量超过55.3%时,Al-Mg-Si合金线强度随着变形量的增大大幅增加;随着拉拔变形量增大,Al-Mg-Si合金线内位错密度逐渐增大,横截面<001>织构逐渐向<111>织构转变,变形初期Al-Mg-Si合金线内存在大量的小角度晶界,变形后期小角度晶界逐渐演化为大角度晶界;Al-Mg-Si合金线强度随变形量的增大而增加的机制为位错强化、织构强化和细晶强化,导致Al-Mg-Si合金线强度与变形量呈现两阶段关系的原因是不同取向差晶界的强化作用差异。

The relationship between strength and microstructure of Al-Mg-Si alloy wire and drawing deformation was studied, and the strengthening mechanism of the Al-Mg-Si alloy wire was analyzed. The results show that the strength of the Al-Mg-Si alloy wire presents two-stage characteristics with the increase of deformation. In the first stage(deformation is less than 55.3%), the strength of the Al-Mg-Si alloy wire increases slowly with the increase of deformation. In the second stage(the deformation is more than 55.3%), the strength of the Al-Mg-Si alloy wire increases rapidly with the increase of deformation. With the increase of drawing deformation, the dislocation density of the Al-Mg-Si alloy wire increases gradually, and the cross section <001> texture changes gradually to <111> texture. At the beginning of deformation, there are a large number of small angle grain boundaries in the alloy wire, and the small angle grain boundaries gradually evolve into large angle grain boundaries in the later stage of deformation. The strengthening mechanisms of the Al-Mg-Si alloy wire after drawing deformation are dislocation strengthening, texture strengthening and grain refinement strengthening. The reason for the two-stage characteristics in the relationship between the strength of the Al-Mg-Si alloy wire and the deformation is the difference of strengthening effect of grain boundaries with various misorientation.