TY - JOUR
T1 - Effects of Recrystallization on Tensile Anisotropic Properties for IN738LC Fabricated by Laser Powder Bed Fusion
AU - Hibino, Shinya
AU - Fujimitsu, Kazushige
AU - Azuma, Makoto
AU - Ishimoto, Takuya
AU - Nakano, Takayoshi
N1 - Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - This study demonstrates the effects of recrystallization on tensile properties and the anisotropy of IN738LC, a typical γ’ precipitation-strengthened alloy, at both room and high temperatures via the laser powder bed fusion process. The nonrecrystallized columnar microstructure, subjected to standard IN738LC heat treatment up to 1120◦ C, and the almost fully recrystallized microstructure, heat-treated at 1204◦ C, were compared. The tensile properties strongly depend on whether recrystallization was completed as well as the tensile direction. This can be explained by microstructure characterization, featuring the Taylor factor in the tensile direction, average grain size estimated by ellipse approximation, and the relationship between the grain shape and tensile direction. The shape of the recrystallized grains and the distribution of coarse MC carbides inside the recrystallized grains were determined by the microstructure in an as-built state. In high-temperature tensile tests conducted in the horizontal direction, the separation of the columnar grains caused a brittle fracture. In contrast, dimples were observed at the fracture surface after recrystallization, indicating scope for further improvement in ductility.
AB - This study demonstrates the effects of recrystallization on tensile properties and the anisotropy of IN738LC, a typical γ’ precipitation-strengthened alloy, at both room and high temperatures via the laser powder bed fusion process. The nonrecrystallized columnar microstructure, subjected to standard IN738LC heat treatment up to 1120◦ C, and the almost fully recrystallized microstructure, heat-treated at 1204◦ C, were compared. The tensile properties strongly depend on whether recrystallization was completed as well as the tensile direction. This can be explained by microstructure characterization, featuring the Taylor factor in the tensile direction, average grain size estimated by ellipse approximation, and the relationship between the grain shape and tensile direction. The shape of the recrystallized grains and the distribution of coarse MC carbides inside the recrystallized grains were determined by the microstructure in an as-built state. In high-temperature tensile tests conducted in the horizontal direction, the separation of the columnar grains caused a brittle fracture. In contrast, dimples were observed at the fracture surface after recrystallization, indicating scope for further improvement in ductility.
KW - IN738LC
KW - MC carbide
KW - anisotropy
KW - heat treatment
KW - laser powder bed fusion
KW - recrystallization
KW - tensile property
UR - http://www.scopus.com/inward/record.url?scp=85132580214&partnerID=8YFLogxK
U2 - 10.3390/cryst12060842
DO - 10.3390/cryst12060842
M3 - 学術論文
AN - SCOPUS:85132580214
SN - 2073-4352
VL - 12
JO - Crystals
JF - Crystals
IS - 6
M1 - 842
ER -