热处理对选区激光熔化制备Al-Mn-Mg-Sc-Zr合金微观组织和力学性能的影响  

Microstructure and Mechanical Properties of Al-Mn-Mg-Sc-Zr Alloy Prepared by Selective Laser Melting with Different Heat Treatment

作　　者：翟梓棫 潘炜 梁博 刘彦涛[1,2,3] 张永忠 Zhai Ziyu;Pan Wei;Liang Bo;Liu Yantao;Zhang Yongzhong(National Engineering&Technology Research Center for Non-Ferrous Metals Composites,China GRINM Co.,Ltd.,Beijing 101407,China;Grinm Metal Composites Technology Co.,Ltd.,Beijing 101407,China;General Research Institute for Nonferrous Metals,Beijing 100088,China)

机构地区：[1]中国有研科技集团有限公司国家有色金属复合材料工程技术研究中心,北京101407 [2]有研金属复材技术有限公司,北京101407 [3]北京有色金属研究总院,北京100088

出　　处：《稀有金属》2024年第3期325-335,共11页Chinese Journal of Rare Metals

基　　金：北京市科技计划项目(Z201100008420012)资助。

摘　　要：利用选区激光熔化(SLM)成形技术制备了Al-Mn-Mg-Sc-Zr合金,测试了不同热处理工艺下材料的显微硬度和拉伸性能,得到力学性能最佳的热处理工艺为300℃/5 h,并利用扫描电镜(SEM)和透射电镜(TEM)分析了热处理对合金组织性能的影响。结果表明:沉积态微观组织由沿沉积高度方向交替生长的柱状晶与等轴晶及细小第二相粒子组成,少量纳米级Al_(3)Sc和Al_(6)Mn粒子分布于晶内。经过热处理后,初生Al_(3)Sc和Al_(6)Mn粒子长大,晶粒尺寸发生轻微的粗化现象。热处理态试样抗拉强度为(556±2.3)MPa,较沉积态试样提高21%;断后伸长率为14.2%±1.2%,较沉积态试样没有明显变化,这主要由于热处理后的大量纳米或微纳米级第二相弥散析出所产生的沉淀强化导致,弥散的第二相同时分布于晶界和晶粒内部。在SLM成形过程中产生的热应力会导致沉积态晶粒内部产生位错,位错会导致沉积态试样的应力-应变曲线在塑性变形阶段出现明显的波动现象,热处理后消除了位错,波动现象消失。热处理降低了合金的残余应力和位错密度,保证了合金的良好塑性。In recent years,the preparation of high strength aluminium alloys using selective laser melting(SLM)process has received increasing attention.In order to obtain SLM-formed Al-Mn-Mg-Sc-Zr alloys with good mechanical properties,the best heat treatment process was obtained to understand the changes in microstructure and mechanical properties before and after heat treatment.AlMn-Mg-Sc-Zr alloy was prepared by SLM,the heat treatment process was optimized based on microhardness and tensile properties tests,and the effect of the optimized heat treatment process on the microstructure and properties of the alloy was analyzed using scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The microstructure of the as-deposited samples and the alloy samples obtained from the optimum heat treatment process were compared.SEM was used for microstructure observation and the accompanying electron backscattering spectrometer(EBSD)and electron emission channel correlation(ECC)were used for grain size and phase distribution analysis.TEM and the accompanying energy spectrometer(EDS)were used to analyze the internal grain and intergranular precipitation phases composition.The microstructure of heat-treated alloy samples was observed and compared with as-deposited samples.It could be determined that the characteristic columnar-equiaxed crystal structure was preserved,but the second phase particles were coarsened and precipitated more.Combining the characteristics of crystal morphology and the effect of heat on crystal growth,the reasons for the changes in the morphology and quantity of the second phase were proposed.Combined with EBSD analysis,the phenomenon that second-phase particles existed both at grain boundaries and in specific directions within grains was explained.The second phase particles in the columnar crystal region were observed using TEM.Combined with EDS analysis,it was determined that the second phase particles in the as-deposited alloy was Al_(6)Mn phase.The second phase particles in the equiaxed cry

关 键 词：选区激光熔化(SLM) 热处理 Al-Mn-Mg-Sc-Zr 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]