固溶时效处理对稀土铝合金力学性能及组织的影响

Influence of solution treatment and aging on mechanical properties and microstructure of rare earth aluminum alloy

研究了4种厚度稀土铝合金板的固溶时效处理工艺(480℃固溶水冷和120℃×24 h时效处理),对热处理前、后的合金进行了室温拉伸试验,通过EBSD对微观组织进行了定性和定量研究,并对拉伸断口形貌进行了观察分析。结果表明,该固溶时效处理工艺对提高稀土铝合金的强度效果明显,对3.0 mm厚板料的增强效果最为显著,此外对合金的塑性具有一定的提升作用;固溶时效处理后,3.0 mm厚合金相比1.2 mm厚合金,其各向异性更强,大角度晶界角和小角度晶界角的数量更多,晶界总长度增加,平均晶粒尺寸更小。固溶时效处理对试验稀土铝合金有良好的细晶强化和位错强化效果。热处理前试验稀土铝合金的断裂方式均为韧性断裂,3.0 mm厚合金显示出比1.2 mm厚合金更好的塑性;经固溶时效处理后,1.2 mm厚合金试样的断口形貌发生变化,材料塑性进一步提高,3.0 mm厚合金的塑性则相比热处理前有所降低。

Solution treatment and aging process(solution treating at 480℃for different time,water cooling,and aging at 120℃for 24 h)of four thicknesses of rare earth aluminum alloy plates were studied,room temperature tensile tests were conducted on the alloy before and after heat treatment.The microstructure was qualitatively and quantitatively studied through EBSD,and the tensile fracture morphology was observed and analyzed.The results show that the solution treatment and aging process has a significant effect on improving the strength of rare earth aluminum alloy,with the most significant strengthening effect on the plate with thickness of 3.0 mm,in addition,it has a certain improvement effect on the plasticity of the alloy.After solution treatment and aging,the alloy with a thickness of 3.0 mm has stronger anisotropy compared to the alloy with a thickness of 1.2 mm,with more high and low angle grain boundaries,increased total length of grain boundaries,and smaller average grain size.Solution treatment and aging has a good effect on fine grain strengthening and dislocation strengthening of the rare earth aluminum alloy.The fracture mode of the rare earth aluminum alloy before heat treatment is ductile fracture,and the alloy with a thickness of 3.0 mm shows better plasticity than the 1.2 mm thick alloy.After solution treatment and aging,the fracture morphology of the 1.2 mm thick alloy specimen changes,and the plasticity further improves,while the plasticity of the 3.0 mm thick alloy decreases compared to that before heat treatment.