Multivariate relationships between microstructure evolution and strengthening mechanisms in laser powder bed fusion of Al-Mn-Sc alloy:towards improved fatigue performance  

作　　者：Huaping Tang Chaofeng Gao Shiheng Zhang Xiaojing Xiong Sheng Cao Xiaopeng Wu Yunjie Bi Jeremy Heng Rao 

机构地区：[1]Institute of Advanced Additive Manufacturing,Ji Hua Laboratory,Foshan,Guangdong,528200,China [2]Department of Mechanical Engineering,College of Engineering,Shantou University,Shantou,Guangdong,515063,China [3]School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China

出　　处：《Light(Advanced Manufacturing)》2024年第1期3-18,共16页光（先进制造）（英文）

基　　金：financially supported by Ji Hua Laboratory“Development of additive manufactured core process and special equipment for key parts of aero-engines”(No.X190351TM190);the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515011597).

摘　　要：The effects of direct aging treatment(at 300℃ for 5 hours)on selective laser melted(SLMed)Al-4.5Mn-1.5Mg-0.9Sc-0.2Zr alloy were investigated in this work,with the microstructure,fatigue behaviors,and fracture characteristics examined to determine the primary cause of fatigue crack source.The results revealed that the microstructure of the investigated alloy comprised fine equiaxed and columnar grains.Upon aging treatment,a significant number of nano-scaled Al3(Sc,Zr)precipitates were dispersed within the grains,leading to a substantial increase in strengths.The yield strength improved from 431 MPa to 568 MPa,representing an increase of more than 32%,while the fatigue strength improved from 180 MPa to 220 MPa after aging treatment.Nevertheless,the fracture toughness decreased significantly from 25.1 MPa·√m to 12.3 MPa·√m.The results of the fatigue fracture characteristics indicate that the Mn-rich phase and the formation of defects such as pores and poor powder fusion are the sources of fatigue cracking.Although direct aging treatment can significantly increase the yield strength,decrease the rate of fatigue crack propagation,and thus improve the fatigue performance,it deteriorates the fracture toughness,and thus shortens the fatigue life of the alloy as well.

关 键 词：Selective laser melting Al-Mn-Sc alloys High-cycle fatigue 

分 类 号：TN24[电子电信—物理电子学]