TY - JOUR
T1 - Stability of vacancies in β-type Ti-15Mo-5Zr-3Al alloy fabricated via laser powder bed fusion
AU - Mizuno, Masataka
AU - Sugita, Kazuki
AU - Do, Kousuke
AU - Ishimoto, Takuya
AU - Nakano, Takayoshi
AU - Araki, Hideki
N1 - Publisher Copyright:
© 2023
PY - 2023/12
Y1 - 2023/12
N2 - The structural instability in the β-type titanium alloys could affect the stability of vacancies. The stability of vacancies in a β-type Ti-15Mo-5Zr-3Al alloy, fabricated via laser powder bed fusion (LPBF), was investigated using positron annihilation spectroscopy and first-principles calculations. The observed positron lifetimes were close to the experimental and calculated bulk lifetime of Ti-15Mo-5Zr-3Al, which indicates that vacancies were not detected in Ti-15Mo-5Zr-3Al by positron lifetime measurements. Therefore, for the first time, it has been confirmed that quenched-in vacancies are not introduced in the LPBF-manufactured β-type Ti-15Mo-5Zr-3Al despite the fast cooling rate in LPBF process. This feature is preferable for the structural stability in biomedical and industrial applications. The calculated atomic displacement from the ideal bcc lattice positions decreased in β-type Ti-Mo alloys with increasing Mo concentration, indicating that the bcc structure was stabilized by the added Mo. The calculated vacancy formation energies of Ti atoms in β-type Ti-14.5Mo and Ti-27.0Mo alloys exhibited an increasing trend with an increasing number of neighboring Mo atoms. Mo atoms also increased the migration energies of the neighboring paths of vacancies. The calculated results for Ti-15Mo-5Zr-3Al suggest that, while the bcc structure was stabilized by the Mo atoms in Ti-15Mo-5Zr-3Al, the migration and formation energies were still low enough for the diffusion of vacancies.
AB - The structural instability in the β-type titanium alloys could affect the stability of vacancies. The stability of vacancies in a β-type Ti-15Mo-5Zr-3Al alloy, fabricated via laser powder bed fusion (LPBF), was investigated using positron annihilation spectroscopy and first-principles calculations. The observed positron lifetimes were close to the experimental and calculated bulk lifetime of Ti-15Mo-5Zr-3Al, which indicates that vacancies were not detected in Ti-15Mo-5Zr-3Al by positron lifetime measurements. Therefore, for the first time, it has been confirmed that quenched-in vacancies are not introduced in the LPBF-manufactured β-type Ti-15Mo-5Zr-3Al despite the fast cooling rate in LPBF process. This feature is preferable for the structural stability in biomedical and industrial applications. The calculated atomic displacement from the ideal bcc lattice positions decreased in β-type Ti-Mo alloys with increasing Mo concentration, indicating that the bcc structure was stabilized by the added Mo. The calculated vacancy formation energies of Ti atoms in β-type Ti-14.5Mo and Ti-27.0Mo alloys exhibited an increasing trend with an increasing number of neighboring Mo atoms. Mo atoms also increased the migration energies of the neighboring paths of vacancies. The calculated results for Ti-15Mo-5Zr-3Al suggest that, while the bcc structure was stabilized by the Mo atoms in Ti-15Mo-5Zr-3Al, the migration and formation energies were still low enough for the diffusion of vacancies.
KW - Diffusion
KW - First-principles calculation
KW - Laser powder bed fusion
KW - Migration energy
KW - Ti alloys
KW - Vacancy formation energy
UR - http://www.scopus.com/inward/record.url?scp=85165031744&partnerID=8YFLogxK
U2 - 10.1016/j.addlet.2023.100162
DO - 10.1016/j.addlet.2023.100162
M3 - 学術論文
AN - SCOPUS:85165031744
SN - 2772-3690
VL - 7
JO - Additive Manufacturing Letters
JF - Additive Manufacturing Letters
M1 - 100162
ER -