Double-peak age strengthening of an Al-Mg-Si-Zn alloy processed by laser powder bed fusion  

作　　者：Feipeng Yang Jianying Wang Tao Wen Shilong Huang Lei Zhang Jinhua Wu Jianming Zhen Ling Shan Xixi Dong Hailin Yang 

机构地区：[1]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China [2]College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China [3]Zhejiang Wanfeng Precision Casting Co.,Ltd.,Shaoxing 312400,China

出　　处：《Journal of Materials Science & Technology》2024年第25期82-94,共13页材料科学技术(英文版)

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.52071343);the Leading Innovation and Entrepreneurship Team of Zhejiang Province-Automotive Light Alloy Innovation Team(No.2022R01018)are gratefully acknowledged.

摘　　要：Laser powder bed fusion(LPBF)with a high cooling rate delivers a huge potential in improving the solid solubility limit and subsequent precipitation strengthening.In this work,a double-peak age hardening was observed in the LPBF-processed Al-5Mg-2Si-3Zn alloy,in which the higher hardness value was 176 HV for the second peak and the lower hardness was 169 HV for the first peak.The yield strength was re-markably enhanced from the 349 MPa under as-built condition to the 434 MPa under as-aged condition.It was found that the double peak hardening was highly associated with Zn alloying,which promoted the formation of Zn segregation with overlapping of nanoscale eutectic Mg2 Si cells in the as-built state.The aged microstructures were characterized by the uniformly distributed Zn solute and the precipitation of the secondary lath-shapedβphase,which is responsible for the first peak age strengthening.Further,the pre-existedβin conjunction with the newly formed needle-shaped(Mg,Zn)-rich Guinier-Preston(GP)zone and plate-shapedηprecipitates co-contribute to the strengthening in the second peak.The synergistic strengthening of multiple precipitates is very effective and efficient for the development of additively manufactured aluminium alloys.

关 键 词：Additive manufacturing Aluminium alloy Microstructure Mechanical property Heat treatment 

分 类 号：TG1[金属学及工艺—金属学]