稀土La对6063铝合金组织与时效性能的影响

用硬度(HB、Hv)测试仪、差示扫描量热仪(DSC)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)等方法研究稀土La对6063合金铸态组织、力学性能、时效性能及时效序列的影响.结果表明,稀土La对合金铸锭枝晶组织有明显的细化作用,添加适量的La有利于合金力学性能和改善,并且稀土的加入并没有改变合金的析出顺序,但随着稀土含量的提高,稀土La会消耗大量的Si,并在合金中形成粗大的AlFesiLa化合物,抑制了中间沉淀析出相β″和β′析出,使强化相Mg_2Si减少,反而使合金力学性能降低.

Effect of Rare Earth La on Microstructures and Ageing Characteristics of 6063 Aluminum Alloy

The effect of rare earth La on as-cast structure, mechanical property and the ageing behaviors of 6063 Al alloy are investigated by means of hardness measurement (HB/HV), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM). The results show that La has made the dendritic structrue refined significantly and proper content of La improve the mechanical of the alloy. Furthermore, the ageing precipitation sequence of the matrix alloy is not changed by the addition of the rare earth, but the mechanical performance is decreased and the precipitation of the β" and β' phases are restrained by addition of the excessive La because of the appearance of bulky AlFeSiL, a compound.