选区激光熔化高强Al-(Mn,Mg)-(Sc,Zr)合金成形性及力学性能  

Formability and Mechanical Properties of High-Strength Al-(Mn,Mg)-(Sc,Zr)Alloy Produced by Selective Laser Melting

作　　者：耿遥祥[1] 唐浩 许俊华[1] 张志杰[1] 喻利花[1] 鞠洪博[1] 江乐 简江林 GENG Yaoxiang;TANG Hao;XU Junhua;ZHANG Zhijie;YU Lihua;JU Hongbo;JIANG Le;JIAN Jianglin(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China)

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212003

出　　处：《金属学报》2022年第8期1044-1054,共11页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.52001140和51801079;江苏省自然科学基金项目Nos.BK20180985和BK20180987。

摘　　要：基于选区激光熔化(SLM)技术熔体急冷的特点,通过同时增加(Mn+Mg)和(Sc+Zr)合金化元素的含量,设计了SLM专用Al-(Mn,Mg)-(Sc,Zr)合金,系统研究了时效温度对合金组织和力学性能影响。结果表明,合金表现出良好的SLM成形性,不同激光扫描速率下制备样品的致密度均超过99.0%。样品具有典型的熔池状显微结构,熔池边界为等轴晶,熔池内部包含少量的柱状晶,晶粒的平均尺寸约为4μm。经低温(≤350℃)时效处理后,由于Al_(3)Sc纳米颗粒的大量析出,使得样品的力学性能大幅提升。样品的最大Vickers硬度为(218±5)HV,最大压缩屈服强度和抗压强度分别达到(653±3)和(752±7)MPa,所有样品的压缩延伸率均超过60%。合金的强度超过现有报道的大多数SLM成形铝合金及经T6处理的AA7075铝合金。多种强化机制共同作用使得SLM成形Al-(Mn,Mg)-(Sc,Zr)合金具有高强度。Selective laser melting(SLM)has been widely used in many fields owing to its high manufacturing accuracy and excellent performance.A rapid solidification rate of 103-106 K/s is achieved during the SLM process,resulting in unique microstructures and highly supersaturated solid solutions beyond the normal solubility limits of alloying elements,thereby providing new opportunities for the development of microstructures and optimization of their properties.To date,SLM has been used for manufacturing a wide range of metallic materials,such as Ti-based alloys,superalloys,and stainless steel.However,specific difficulties are associated with melting aluminum powder using a laser owing to the high laser reflectivity,tenacious surface oxide,poor spreadability(particularly of low-density aluminum powder),high ther-mal conductivity,and large freezing ranges of many aluminum alloys.Consequently,high-strength aluminum alloys,such as the 2xxx,6xxx,and 7xxx series,exhibit poor SLM formability.The SLM-formed aluminum alloys that are practically applied in industries at present are limited to the Al-Si base and Al-Mg-(Sc,Zr)alloys.Al-Mg-(Sc,Zr)alloys achieve high strength and ductility with low mechanical anisotropy,thus showing considerable advantages over conventional and SLM-formed Al-Si-Mg alloys.However,the strength of the present SLM-formed aluminum alloys is still lower than that of conventional highperformance ones.Based on the technical characteristics of liquid quenching in SLM,this study focuses on designing high-strength Al-(Mn,Mg)-(Sc,Zr)aluminum alloys specifically for SLM by simultaneously increasing the(Mn+Mg)and(Sc+Zr)contents.The effect of aging treatment on the microstructure and mechanical properties of the SLM-formed alloy was systematically studied.Results show that the alloy exhibits good SLM formability with a relative density of more than 99.0%.A typical multilayer distribution of laser tracks generated in the SLM process can be observed.Few columnar grains are observed in the center of the molten pool,and

关 键 词：选区激光熔化 Al-(Mn Mg)-(Sc Zr)合金 时效处理 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]