Influence of post-heat treatment on the microstructure and mechanical properties of Al-Cu-Mg-Zr alloy manufactured by selective laser melting  

作　　者：Yanfang Wang Xin Lin Nan Kang Zihong Wang Yuxi Liu Weidong Huang 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [2]Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design,MIIT China,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《Journal of Materials Science & Technology》2022年第16期35-48,共14页材料科学技术（英文版）

基　　金：financially supported by the National Key R&D Program of China(No.2018YFB1106300);the National Natural Science Foundation of China(No.51604227);the Fundamental Research Funds for the Central Universities(No.31020180QD130)。

摘　　要：The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutilized.In this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary AlZr.It was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed sample.After direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was precipitated.In contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain region.Meanwhile,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA sample.This subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation strengthening.Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).

关 键 词：Selective laser melting Al-Cu-Mg alloy Heat treatment Microstructure Mechanical properties 

分 类 号：TG156[金属学及工艺—热处理] TG146.21[金属学及工艺—金属学]