TY - JOUR
T1 - Effect of microstructure on the Charpy impact properties of directed energy deposition 300M steel
AU - Liu, Fenggang
AU - Lin, Xin
AU - Shi, Jing
AU - Zhang, Yongjian
AU - Bian, Peiying
AU - Li, Xun
AU - Hu, Yunlong
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/10
Y1 - 2019/10
N2 - Direct manufacturing techniques, such as directed energy deposition (DED), are able to produce complex components efficiently. In this study, microstructure evolution and impact toughness of DED 300M ultra-high strength steel are investigated. The results show that the microstructure of the as-deposited DED 300M ultra-high strength steel is mainly composed of martensite and some blocky bainite. The micro-segregation of elements is observed within the interdendritic area. After heat treatment, the microstructure becomes uniform and consists of martensite and lower bainite. The impact toughness of the as-deposited DED 300M ultra-high strength steel is 9 J/cm2, while it is significantly increased to 25 J/cm2 after heat treatment. Furthermore, it is observed that the fracture mode of the as-deposited sample is quasi-cleavage fracture. During the process of propagation, the main cracks would go across the martensite packet and deflect in the another one, and secondary cracks also deflected in the high-angle grain boundaries. By contrast, the fracture mode of heat-treated DED 300 M steel is ductile fracture.
AB - Direct manufacturing techniques, such as directed energy deposition (DED), are able to produce complex components efficiently. In this study, microstructure evolution and impact toughness of DED 300M ultra-high strength steel are investigated. The results show that the microstructure of the as-deposited DED 300M ultra-high strength steel is mainly composed of martensite and some blocky bainite. The micro-segregation of elements is observed within the interdendritic area. After heat treatment, the microstructure becomes uniform and consists of martensite and lower bainite. The impact toughness of the as-deposited DED 300M ultra-high strength steel is 9 J/cm2, while it is significantly increased to 25 J/cm2 after heat treatment. Furthermore, it is observed that the fracture mode of the as-deposited sample is quasi-cleavage fracture. During the process of propagation, the main cracks would go across the martensite packet and deflect in the another one, and secondary cracks also deflected in the high-angle grain boundaries. By contrast, the fracture mode of heat-treated DED 300 M steel is ductile fracture.
KW - 300M ultra-high strength steel
KW - Directed energy deposition
KW - Fracture mechanism
KW - Impact toughness
UR - http://www.scopus.com/inward/record.url?scp=85069556625&partnerID=8YFLogxK
U2 - 10.1016/j.addma.2019.100795
DO - 10.1016/j.addma.2019.100795
M3 - 文章
AN - SCOPUS:85069556625
SN - 2214-8604
VL - 29
JO - Additive Manufacturing
JF - Additive Manufacturing
M1 - 100795
ER -