TY - JOUR
T1 - レーザービーム粉末床溶融結合法により作製した Ti–6Al–4Nb–4Zr のクリープ挙動
AU - Yamabe–Mitarai, Yoko
AU - Inoue, Takashi
AU - Kuroda, Tomoki
AU - Matsunaga, Sae
AU - Toda, Yoshiaki
AU - Matsunaga, Tetsuya
AU - Ito, Tsutomu
AU - Ozasa, Ryosuke
AU - Ishimoto, Takuya
AU - Nakano, Takayoshi
N1 - Publisher Copyright:
© 2024 The Japan Institute of Metals and Materials.
PY - 2024/9/1
Y1 - 2024/9/1
N2 - Powder bed fusion using a laser beam (PBF–LB) was performed for Ti–6Al–4Nb–4Zr (mass%) developed by our group to improve the oxidation resistance at temperatures greater than 600℃ by adding Nb and Zr to near–α alloys. Microstructure evolution of the PBF–LB samples by heat treatment was investigated, especially for heat treatment duration in the α + β phase, cooling rate, and heat treatment in the β phase. The equiaxed α phase formed during heat treatment along the melting–pool boundaries. The high volume fraction of the α phase and high Nb contents in the β phase was obtained by slow cooling (furnace cooling) compared with fast cooling (air cooling). The α/β lamellar structure formed in the melting pool boundaries with 100 µm in size and no equiaxed α phase formed along the boundaries by heat treatment in the β phase regime. Creep life at 600℃ and 137 MPa was similar for the air–cooled and furnace–cooled samples, but the slightly slower deformation was obtained in the furnace–cooled sample. Creep life of the sample heat treated in the β phase region drastically increased due to the absence of the equiaxed α phase. Dominant deformation mechanism of creep was grain boundary sliding. The small equiaxed α phase accelerated grain boundary sliding.
AB - Powder bed fusion using a laser beam (PBF–LB) was performed for Ti–6Al–4Nb–4Zr (mass%) developed by our group to improve the oxidation resistance at temperatures greater than 600℃ by adding Nb and Zr to near–α alloys. Microstructure evolution of the PBF–LB samples by heat treatment was investigated, especially for heat treatment duration in the α + β phase, cooling rate, and heat treatment in the β phase. The equiaxed α phase formed during heat treatment along the melting–pool boundaries. The high volume fraction of the α phase and high Nb contents in the β phase was obtained by slow cooling (furnace cooling) compared with fast cooling (air cooling). The α/β lamellar structure formed in the melting pool boundaries with 100 µm in size and no equiaxed α phase formed along the boundaries by heat treatment in the β phase regime. Creep life at 600℃ and 137 MPa was similar for the air–cooled and furnace–cooled samples, but the slightly slower deformation was obtained in the furnace–cooled sample. Creep life of the sample heat treated in the β phase region drastically increased due to the absence of the equiaxed α phase. Dominant deformation mechanism of creep was grain boundary sliding. The small equiaxed α phase accelerated grain boundary sliding.
KW - creep
KW - deformation mechanism
KW - heat treatment
KW - heat–resistant Ti alloys
KW - selective laser melting
UR - http://www.scopus.com/inward/record.url?scp=85201880181&partnerID=8YFLogxK
U2 - 10.2320/jinstmet.JA202406
DO - 10.2320/jinstmet.JA202406
M3 - 学術論文
AN - SCOPUS:85201880181
SN - 0021-4876
VL - 88
SP - 163
EP - 170
JO - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
JF - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
IS - 9
ER -