预时效处理对AlZnMgCu铝合金自然时效和烘烤硬化行为的影响  

Influence of pre-aging on natural aging and bake hardening behavior of AlZnMgCu aluminum alloy

作　　者：徐向美 王琪晨 Xu Xiangmei;Wang Qichen(College of Information Engineering,Yantai Institute of Technology,Yantai Shandong 264005,China;CIMC Offshore Engineering Institute Company Ltd.,Yantai Shandong 264670,China)

机构地区：[1]烟台理工学院信息工程学院,山东烟台264005 [2]中集海洋工程研究院有限公司,山东烟台264670

出　　处：《金属热处理》2023年第10期188-192,共5页Heat Treatment of Metals

摘　　要：研究了一种AlZnMgCu铝合金的自然时效行为,利用预时效处理降低自然时效过程的硬化效果,提升人工时效过程的硬化效应。利用金相显微镜和透射电镜表征了微观组织结构,测试了显微硬度和拉伸性能。结果表明,预时效处理提高了AlZnMgCu铝合金的初始硬度,但经历12天的自然时效后,最终硬度反而小于固溶后直接自然时效的硬度,降低了24%(120℃预时效);预时效处理后的试样,经自然时效和180℃×20 min的人工时效处理后,屈服强度和抗拉强度分别增大了165 MPa和48 MPa,提高了55.9%和11.2%。固溶+自然时效处理后,基体内GP区尺寸大小不一,分布不均,而经预时效处理后,GP区尺寸和分布均匀,与α-Al基体呈共格关系;预时效+自然时效+人工时效后,η′相粒子尺寸均匀且弥散分布,与α-Al基体呈半共格关系,起到了明显的时效硬化作用。Natural aging behavior of the AlZnMgCu aluminum alloy was investigated,and the hardening effect of natural aging was reduced by pre-aging treatment,which improved the final hardening effect of artificial aging process.The microstructure was characterized by using OM and TEM,the microhardness and tensile properties were tested.The results indicate that pre-aging treatments improve the initial hardness of the AlZnMgCu alloy,but after natural aging for 12 d,the final hardness is actually lower than that of direct natural aging after solid solution,which is reduced by 24%(pre-aging at 120℃).After pre-aging treatment,the yield strength and tensile strength of the specimen increase by 165 MPa and 48 MPa and by 55.9% and 11.2%,respectively,after natural aging and 180℃×20 min artificial aging treatment.After solid solution plus natural aging treatment,the distribution of GP zone in the matrix is uneven,while after pre-aging treatment,the size and distribution of GP zone are relatively uniform and exhibits a coherent relationship withα-Al matrix.After pre-aging,natural aging,and artificial aging,η′phase particles are uniform and dispersed,and exhibit a semi-coherent relationship withα-Al matrix,which plays a significant role in aging hardening.

关 键 词：AlZnMgCu铝合金 预时效 自然时效 烘烤硬化 

分 类 号：TG156.2[金属学及工艺—热处理]