预时效+冷轧变形+再时效对6061铝合金微观组织和力学性能的影响  

EFFECT OFTHE THERMO-MECHANICALTREATMENT OF PRE-AGEING,COLD-ROLLING AND RE-AGEING ON MICROSTRUCTURES AND MECHANICAL PROPERTIES OF 6061 Al ALLOY

作　　者：李海[1,2] 毛庆忠 王芝秀[1,3,2] 苗芬芬[1] 方必军[1] 宋仁国[1,2] 郑子樵[3] 

机构地区：[1]常州大学材料科学与工程学院,常州213164 [2]常州大学江苏省材料表面技术重点实验室,常州213164 [3]中南大学材料科学与工程学院,长沙410083

出　　处：《金属学报》2014年第10期1244-1252,共9页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展计划项目2005CB623705;国家自然科学基金项目51301027;江苏省高校自然科学基金项目14KJB430002资助~~

摘　　要：采用硬度测试、拉伸实验、XRD分析和TEM观察等方法,研究了一种新型形变热处理(预时效+冷轧变形+再时效)对时效硬化型铝合金微观组织和力学性能的影响.结果表明,这种形变热处理不仅能够大幅度提高6061铝合金强度,还能使其保持良好塑性.经过优化处理(180℃,2 h欠时效+75%压下量冷轧变形+100℃,48 h再时效),6061铝合金的抗拉强度和屈服强度分别为560和542 MPa,延伸率为8.5%.微观组织观察表明,合金强度的提高来源于析出强化、位错强化、位错胞强化和高Taylor因子的综合作用;相对于冷轧状态,延伸率的改善则与再时效过程中强化相的再析出和位错的轻微回复有关.In order to improve mechanical properties of age-hardenable Al alloys markedly based on the conventional processing conditions,a novel thermo-mechanical treatment,which was consisted of pre-ageing,coldrolling and re-ageing,was proposed in the present work.The effects of the thermo-mechanical treatment on microstructure evolution and mechanical properties of the 6061 Al alloy were investigated further by hardness measurement,tensile testing,XRD,TEM and HRTEM.It was shown that both the increased strength and elongation of the6061 Al alloy were achieved simultaneously by the thermo-mechanical treatment.Especially,after the combination of under-ageing at 180 ℃ for 2 h,cold-rolling with the thickness reduction of 75% and re-ageing at 100 ℃ for 48 h,the ultimate tensile strength and yield strength of the alloy were 560 and 542 MPa,respectively,and the elongation was about 8.5%.The strength increment of the thermo-mechanically treated 6061 Al alloy was attributed mainly to the additional introduction of dislocation strengthening,dislocation cell strengthening and high Taylor factor value except for precipitation strengthening as compared to the conventional peak-aged alloy.Furthermore,the improved elongation of the thermo-mechanically treated 6061 Al alloy was mainly due to both the re-precipitation of strengthening precipitates and slight recovery of dislocations during re-ageing,which increased the accumulation ability of dislocations during the tensile deformation.

关 键 词：铝合金 形变热处理 力学性能 微观组织 强化机制 

分 类 号：TG147[一般工业技术—材料科学与工程]