新型Al-Mg-Si-Cu-Zn合金板材组织、织构和性能的优化调控  

Optimization and Controlling on the Microstructure,Texture and Properties of an Advanced Al-Mg-Si-Cu-Zn Alloy Sheet

作　　者：陈懿[1] 郭明星[1] 易龙[1] 袁波[1] 李高洁[1] 庄林忠[1] 张济山[1] CHEN Yi GUO Mingxing YI Long YUAN Bo LI Gaojie ZHUANG Linzhong ZHANG Jishan(State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China)

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《金属学报》2017年第8期907-917,共11页Acta Metallurgica Sinica

基　　金：国家重点研发计划项目No.2016YFB0300801;国家自然科学基金项目Nos.51301016和51571023;国家高技术研究发展计划项目No.2013AA032403;北京自然科学基金项目No.2172038~~

摘　　要：通过OM、SEM、TEM观察以及EBSD和力学性能测试等手段研究了不同热加工工艺对Al-Mg-Si-Cu-Zn合金板材组织、织构和成形性能,以及固溶淬火后等温时效对其析出行为的影响规律。结果表明,2种热加工工艺对T4P预时效态合金的强度和应变硬化指数n基本无影响,但是对平均塑性应变比rˉ、Δr以及不同方向延伸率影响显著;不同热加工过程对合金组织和织构演化均有影响,成形性能较好的固溶淬火态合金板材平均晶粒尺寸略大且呈双模型晶粒尺寸分布特征,其织构组分较多,但是强度较低。对该淬火态合金进行185℃人工时效20 min,其硬度即可升高65 HV,进一步时效到5 h达到峰值硬度132 HV,对应的拉伸性能可达Rp=318 MPa,Rm=364 MPa,A=13%,拉伸断口为典型的塑性断裂。该合金在185℃时效时仍以Mg-Si相析出为主,如b"、b'和Q'相等,峰时效后b"相主要沿b轴方向生长,最后转化为b'和Q'相,合金表现出较好的时效稳定性。To reduce the weight of car body, AI-Mg-Si-Cu series alloys have been widely used to pro- duce outer body panels of automobiles due to their favorable high-strength-to-weight ratio, corrosion re- sistance and good formability. Moreover, the strength of AI-Mg-Si-Cu series alloys can be enhanced by ar- tificial ageing treatments. However, their formability and final strengths still need to be further improved compared to steels, which are the major obstacles to wide-scale application of aluminum in the automo- tive fields. In this work, both the effect of different thermomechanical processes on formability, microstruc- ture and texture of AI-Mg-Si-Cu-Zn alloy, and the influence of ageing treatment on its precipitation behav- ior were studied through mechanical property tests, OM, SEM, TEM and EBSD measurements. The resuits reveal that both the strengths and strain-hardening component n value of the T4P treated alloys are not affected by the two thermomechanical processes, but the F, Ar and elongations in the different direc- tions are significantly affected. The microstructure and texture evolution of the alloy in the two thermome- chanical processes are different from each other. Both the microstructure of a little coarser and bi-modal grain size distribution, and the texture characteristics of much more components but with quite lower in- tensities can be seen in the solution treated alloy sheet which possesses a better formability after the T4P treatment. The hardness increment of 65 HV can be achieved in the quenched alloy after artificial ageing treatment of 185 ℃, 20 min. And then the peak-ageing state can be obtained after ageing 5 h, the hardness, yield strength, ultimate tensile strength and elongation, are as follows, 132 HV, 318 MPa, 364 MPa and 13%, respectively, and ductile fracture is the main fracture feature as observed by SEM ex- amination of fracture surface. Mg-Si precipitates, such as ,β″ ,β＇ and Q＇ phases, are still the main precipi- tates formed after artificial aging at 185℃, and

关 键 词：Al-Mg-Si-Cu-Zn合金 热加工 织构 成形性能 沉淀析出 

分 类 号：TG146.2[一般工业技术—材料科学与工程]