保压压力对7075铝合金后续时效行为的影响  

Effect of Holding Pressure on Subsequent Aging Behavior of 7075 Aluminum Alloy

作　　者：陈文轩 李兵 徐飞越 张红霞 邢俊峰 CHEN Wenxuan;LI Bing;XU Feiyue;ZHANG Hongxia;XING Junfeng(School of Materials Science and Engineering,Hubei University of Automotive Technology,Hubei Shiyan 442002,China;Avita Technology(Chongqing)Co.,Ltd.,Chongqing 401120,China)

机构地区：[1]湖北汽车工业学院材料科学与工程学院,湖北十堰442002 [2]阿维塔科技(重庆)有限公司,重庆401120

出　　处：《精密成形工程》2025年第1期60-67,共8页Journal of Netshape Forming Engineering

基　　金：湖北省重点研发项目(2021BAB019);湖北省科技重大专项(2022AAA001)。

摘　　要：目的探究温热成形中保压压力对7075高强铝合金后续时效行为的影响,结合铝合金固溶处理的特点,采用平板压淬实验来模拟实际热成形过程中的冷却条件。对7075高强铝合金进行不同保压压力的研究,以期得到7075铝合金板材固溶成形后的最佳保压压力参数,以及不同保压压力条件下的时效硬化行为和微观组织演变特征,进而为实际生产中的热成形-淬火一体化工艺提供理论指导和工艺优化参考。方法首先对7075铝合金板进行固溶处理和平板压淬实验,再进行后续时效处理。通过金相观察、准静态单轴拉伸测试、显微维氏硬度计和扫描电镜等手段研究了不同保压压力对后续时效处理合金力学性能和组织的影响。结果随着保压压力的升高,晶粒尺寸逐步减小,时效硬化响应显著,峰值硬度呈现逐渐下降的趋势。当保压压力为10 MPa时,经150℃/6 h的人工时效后,材料在强度和塑性之间取得了相对平衡,其抗拉强度为580.9 MPa,屈服强度达到538.6 MPa,断后伸长率达到12.2%。能获得这样较为理想的强塑性匹配是由于当保压压力设定为10 MPa时,合金中η′相数量增多且分布呈现相对弥散,可以阻碍位错运动进而达到强化的效果,但合金塑性会有一定的牺牲。拉伸断口分析结果表明,在保压压力一定时,同一时效制度下的合金韧窝数量随时效时间的延长而减少且深度变浅,材料的塑性下降。结论保压压力对合金的晶粒尺寸、时效硬化及力学性能有显著影响。特别是在10 MPa保压压力下,合金表现出较好的强度与塑性平衡,为7075铝合金热成形-淬火工艺的优化提供了重要参考,尤其是在保压压力选择方面。In order to explore the effect of holding pressure on the subsequent aging behavior of 7075 high strength aluminum alloy in warm forming,combined with the characteristics of solid solution treatment of aluminum alloy,the work aims to simulate the cooling conditions in the actual hot forming process by plate pressure quenching experiment and study the 7075 high strength aluminum alloy under different holding pressure,in order to obtain the optimal holding pressure parameters of 7075 aluminum alloy plate after solid solution forming,as well as its age hardening behavior and microstructure evolution characteristics under different holding pressure conditions,thus providing theoretical guidance and process optimization reference for the hot forming-quenching integration process in actual production.The 7075 aluminum alloy plate was firstly subject to solid solution treatment and plate pressure quenching experiments,and then followed by aging treatment.The effects of different holding pressure on the mechanical properties and microstructure of the alloy after subsequent aging treatment were studied by metallographic observation,quasi-static uniaxial tensile test,micro-Vickers hardness tester and scanning electron microscope.With the increase of holding pressure,the grain size gradually decreased,the aging hardening response was significant,and the peak hardness gradually decreased.When the holding pressure was 10 MPa,the alloy had a relative balance between strength and plasticity after artificial aging at 150℃/6 h,and its tensile strength was 580.9 MPa,yield strength was 538.6 MPa and elongation after fracture reached 12.2%.The ideal matching of strength and plasticity could be obtained because when the holding pressure was set to 10 MPa,the number ofη'phases in the alloy increased and the distribution was relatively dispersed,which could hinder the dislocation movement and achieve the strengthening effect,but the plasticity of the alloy would be sacrificed to some extent.The tensile fracture analysis showed that

关 键 词：7075铝合金 保压压力 时效行为 微观组织 力学性能 

分 类 号：TG166.3[金属学及工艺—热处理]