Microstructural origin of high strength and high strain hardening capability of a laser powder bed fused AlSi10Mg alloy  

作　　者：C.Li W.X.Zhang H.O.Yang J.Wan X.X.Huang Y.Z.Chen 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [2]Chongqing University,Chongqing 400044,China [3]Ningbo Institute of Northwestern Polytechnical University,Ningbo 315103,China [4]Suzhou Yunjing Metal Tech.Ltd.,Suzhou 215024,China

出　　处：《Journal of Materials Science & Technology》2024年第30期194-206,共13页材料科学技术(英文版)

基　　金：the National Key Research and Development Program(No.2022YFB3404203);the National Natural Science Foundation of China(Nos.52071262,52101049,52301197,52234009);the Qinchuangyuan"cientist+Engineer"Team Development of Shaanxi Province(No.2022KXJ-020);the Advanced Development of Aluminum Alloy Filler Materials used in welded High-end Lightweight Constructions-Research&Industrial implementation(No.2022Z109).

摘　　要：Compared to a cast AlSi10Mg alloy,a laser powder bed fused(LPBF)AlSi10Mg alloy shows superior yield strength and strain hardening capability.However,the underlying microstructure origin has not been comprehensively understood.In this work,the microstructural evolution of an LPBF AlSi10Mg alloy dur-ing tensile deformation was investigated.Synchrotron X-ray diffraction characterization shows that both stress and strain exhibit significant partition between an Al phase and a Si phase upon tensile deforma-tion.This leads to a significant strain gradient between those two phases,which is evident by the high density of dislocations in the cell boundaries of the deformed alloy.The strain gradient results in long-range internal stress,also known as back stress,in the cell boundaries,and in turn leads to enhanced strength and strain hardening in the LPBF AlSi10Mg alloy.Quantitatively analyses via loading-unloading-reloading tests show that during the tensile deformation,the back stress contributes 135 MPa to the yield strength of the alloy,which continuously increases with increasing the strain beyond the yielding point.This work illuminates the microstructural origin of the back stress in the LPBF AlSi10Mg alloy,i.e.the back stress arises from the stress/strain partition between the Al and Si phases in the cellular structures,and the back stress leads to significant strengthening of the alloy upon tensile deformation.This work may also provide guidance for manipulating the mechanical properties of additively manufactured Al-Si alloys for specific application needs.

关 键 词：AlSi10Mg alloy Laser powder bed fusion Strengthening mechanism Plastic deformation 

分 类 号：TG1[金属学及工艺—金属学]