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制备了含稀土La的6063铝合金,并研究了La含量对铝合金的显微组织及时效后硬度、抗拉强度和伸长率的影响。研究表明,稀土La对6063合金晶粒有良好的细化作用,在添加La的铝合金组织中,一部分较大的析出相是Al Si Mg Fe化合物,且铁含量较高;另一部分析出相是Al Si Mg Fe La的复杂化合物,其形状多呈较小的粒状。200℃等温时效时,随着时效时间的延长,铝合金硬度迅速升高,在120 min左右达到最大。同时,随着La含量的增加,合金的硬化峰值上升,当La含量为0.2 wt%左右时,时效硬化峰值达到最高。另外,加入适量La可增加合金的抗拉强度和伸长率。未添加La的铝合金其断口组织分布着较大的不规则韧窝,而添加少量La的铝合金其断口上细小的韧窝增多。
6063 aluminum alloy containing rare earth La was prepared and the effect of La content on the microstructure and hardness, tensile strength and elongation after aging of the aluminum alloy was studied. The results show that rare earth La has good refinement effect on 6063 alloy grains. In the aluminum alloy with La addition, some of the larger precipitates are Al Si Mg Fe compounds with higher iron content. The other precipitates are Al Si Mg Fe La complex compounds, the shape of the smaller granular. When isothermal aging at 200 ℃, the hardness of aluminum alloy increases rapidly with the aging time, reaching the maximum at about 120 min. At the same time, with the increase of La content, the hardening peak of the alloy increases. When the La content is about 0.2 wt%, the peak value of age hardening reaches the highest. In addition, adding an appropriate amount of La can increase the tensile strength and elongation of the alloy. The aluminum alloy without La had larger irregular dimples distributed on the fracture surface, whereas the small dimples on the fracture surface increased with the addition of a small amount of La alloy.