TY - JOUR
T1 - Reducing directionally arranged substructure induced anisotropic mechanical properties of Hastelloy X superalloy fabricated by laser directed energy deposition
AU - Zhu, Jiaxi
AU - Kang, Nan
AU - Li, Dou
AU - Li, Bo
AU - Feng, Zhenyu
AU - Zhong, Hong
AU - Li, Shuangming
N1 - Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2023/1/18
Y1 - 2023/1/18
N2 - In this study, the effects of solution treatment (ST) on the microstructure and anisotropic mechanical properties of Hastelloy X fabricated by laser directed energy deposition (L-DED) were investigated. The microstructure of the as-deposited (AD) sample presented coarse granular grains aligned with the deposition direction. Due to the segregation of Mo and Cr elements, a special cellular-structure was formed in the inter-dendritic region, along with the strip-like carbides consisting of both M23C6 and M6C carbides. The cellular-structure homogenized rapidly after the ST. In detail, as the ST temperature increased, recrystallization generally occurred. Meanwhile, the strip carbides began to gradually dissolve and dissociate into dispersed particles which led to a drop in microhardness from 220 HV to 161 HV. The room temperature tensile results showed that the yield strength in the transversal direction (TD) and longitudinal direction (LD) decreased with the increase of ST temperature, reaching a minimum value of 285 MPa after the ST at 1175 °C. In addition, the ultimate tensile strength of the LD and TD samples reached maximum values of 693 MPa and 703 MPa at 1150 °C, respectively. It should be noted that the elongation of the low ductile TD sample can be improved significantly from 30% to 75% after the ST at 1175 °C. Therefore, it can be concluded that the anisotropy within the TD and LD samples can be effectively eliminated by controlling the cellular-structure, grain-structure, and carbide morphology during ST.
AB - In this study, the effects of solution treatment (ST) on the microstructure and anisotropic mechanical properties of Hastelloy X fabricated by laser directed energy deposition (L-DED) were investigated. The microstructure of the as-deposited (AD) sample presented coarse granular grains aligned with the deposition direction. Due to the segregation of Mo and Cr elements, a special cellular-structure was formed in the inter-dendritic region, along with the strip-like carbides consisting of both M23C6 and M6C carbides. The cellular-structure homogenized rapidly after the ST. In detail, as the ST temperature increased, recrystallization generally occurred. Meanwhile, the strip carbides began to gradually dissolve and dissociate into dispersed particles which led to a drop in microhardness from 220 HV to 161 HV. The room temperature tensile results showed that the yield strength in the transversal direction (TD) and longitudinal direction (LD) decreased with the increase of ST temperature, reaching a minimum value of 285 MPa after the ST at 1175 °C. In addition, the ultimate tensile strength of the LD and TD samples reached maximum values of 693 MPa and 703 MPa at 1150 °C, respectively. It should be noted that the elongation of the low ductile TD sample can be improved significantly from 30% to 75% after the ST at 1175 °C. Therefore, it can be concluded that the anisotropy within the TD and LD samples can be effectively eliminated by controlling the cellular-structure, grain-structure, and carbide morphology during ST.
KW - Anisotropy
KW - Hastelloy X superalloy
KW - Laser directed energy deposition
KW - Mechanical properties
KW - Solution treatment
UR - http://www.scopus.com/inward/record.url?scp=85143805420&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2022.144461
DO - 10.1016/j.msea.2022.144461
M3 - 文章
AN - SCOPUS:85143805420
SN - 0921-5093
VL - 862
JO - Materials Science and Engineering: A
JF - Materials Science and Engineering: A
M1 - 144461
ER -