固溶处理和人工时效对Al-Cu合金显微组织和力学性能的影响

摘要

In order to achieve good mechanical properties of Al-Cu alloys such as high strength and good toughness,precipitation hardening and artificial aging treatment were applied.As defined by the T6 heat treatment,the standard artificial aging treatment for Al-Cu alloy followed heat treatments of solution treatment at 510-530 ℃ for 2 h,quenching in water at 60 ℃ and then artificial aging at 160-190 ℃ for 2-8 h.The effects of solution treatment and artificial aging on the microstructure and mechanical properties of Al-Cu alloy were studied by optical microscopy (OM),scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS),transmission electron microscopy (TEM) and tensile test.The results of solution treatment indicate that the mechanical properties of Al-Cu alloy increase and then decrease with the increase of solution temperature.This is because the residual phases dissolve gradually into the matrix,and the fraction of the precipitation and the size of the re-crystallized grain increased.Compared to the solution temperature,the solution holding time has less effect on the microstructure and the mechanical properties of Al-Cu alloy.The artificial aging treatments were conducted at 160-180 ℃ for 2-8 h.The results show that the ultimate tensile strength can be obtained at 180 ℃ for 8 h.Ultimate tensile strength increased with increasing time or temperature.Yield strength was found as the same as the ultimate tensile strength result.%对Al-Cu合金进行析出强化和人工时效处理以获得优异的力学性能,如高的强度、好的韧性.其热处理工艺条件为:510～530 ℃固溶处理2h; 60℃水淬；160～190℃人工时效2～8 h.采用光学显微镜、扫描电镜、能谱分析、透射电镜和拉伸实验对经固溶和人工时效处理的Al-Cu合金的组织和力学性能进行表征.固溶处理实验结果表明,Al-Cu合金的力学性能随着固溶处理温度的升高先增加,然后降低.这是由于Al-Cu合金的残余相逐渐溶解进入基体中,从而导致析出相的数量和再结晶晶粒尺寸不断增加.相较于固溶处理温度,固溶处理时间对Al-Cu合金的影响较小.人工时效处理实验结果表明,合金经180℃时效8h,可以获得最大的拉伸强度.合金的最大拉伸强度和屈服强度随着时效时间的延长和温度的升高而升高.