挤压态6061铝合金的力学性能及显微组织

对挤压态6061铝合金分别进行了固溶处理和时效处理,采用万能试验机测试了其力学性能,通过SEM和TEM表征了合金的微观组织,研究了不同热处理条件下挤压态6061铝合金的组织演变规律。结果表明:固溶和时效处理后的挤压态6061铝合金均表现出明显的力学性能各向异性,且时效处理能有效提升合金的强度;同时,经时效处理后的挤压态6061铝合金表现出应变速率敏感性,而固溶处理的挤压态6061铝合金则无明显的应变速率敏感性;固溶处理和时效处理的挤压态6061铝合金的晶粒形态为等轴晶,但是有大小两种晶粒尺寸等级,大晶粒尺寸可达200 μm,小晶粒尺寸则小于10 μm。固溶和时效处理的挤压态6061铝合金均由较强的{001}<100>立方织构和较弱的{011}<100>高斯织构组成,且种类和强度相同;拉伸变形后的6061铝合金出现了大量的位错堆积,而经时效处理的合金中均匀分布短棒状的析出相能有效阻碍位错的运动,提高材料的变形抗力。

Mechanical properties and microstructure of extruded 6061 aluminum alloy

As-extruded 6061 aluminum alloy was subjected to solution treatment and aging treatment,respectively.The mechanical properties of the alloy were tested by universal testing machine,and the microstructure was characterized by means of SEM and TEM to investigate the microstructure evolution law of the alloy in different heat treatment states.The results show that the extruded 6061 aluminum alloy after solution treatment and aging treatment show obvious anisotropic mechanical properties,and aging treatment can effectively improve the strength of the alloy.At the same time,the extruded alloy after aging treatment shows strain rate sensitivity,however,the alloy after solution treatment has no obvious strain rate sensitivity.The extruded 6061 aluminum alloy after solution treatment and aging treatment are composed of equiaxed grains with two kinds of grain sizes,which the larger one being up to 200 μm and the smaller one being less than 10 μm.The types and strength of texture components of the extruded 6061 aluminum alloy solution-treated or as-aged are the same,both are composed of strong {001} <100>cubic texture and weak {011} <100>Goss texture.After tensile deformation,a large number of dislocations pile up,and the short rod like precipitates will be evenly distributed in the alloy after aging treatment,which can effectively block the movement of dislocations and improve the deformation resistance of materials.