Influence of Nonmetallic Interstitials on the Phase Transformation between FCC and HCP Titanium: A Density Functional Theory Study
Mengmeng Yang,
Jianan Hu,
Shuo Cao,
Guang Feng,
Yi Yang,
Renci Liu,
Shujun Li,
Fu Zhao,
Aihan Feng,
Qingmiao Hu,
Aijun Huang,
Hao Wang
Affiliations
Mengmeng Yang
Interdisciplinary Centre for Additive Manufacturing (ICAM), School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China
Jianan Hu
Interdisciplinary Centre for Additive Manufacturing (ICAM), School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China
Shuo Cao
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Guang Feng
Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
Yi Yang
Interdisciplinary Centre for Additive Manufacturing (ICAM), School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China
Renci Liu
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Shujun Li
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Fu Zhao
Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
Aihan Feng
School of Materials Science and Engineering, Tongji University, Shanghai 201804, China
Qingmiao Hu
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Aijun Huang
Monash Centre for Additive Manufacturing (MCAM), Monash University, Notting Hill, VIC 3168, Australia
Hao Wang
Interdisciplinary Centre for Additive Manufacturing (ICAM), School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China
In addition to the common stable and metastable phases in titanium alloys, the face-centered cubic phase was recently observed under various conditions; however, its formation remains largely unclarified. In this work, the effect of nonmetallic interstitial atoms O, N, C and B on the formation of the face-centered cubic phase of titanium was investigated with the density functional theory. The results indicate that the occupancy of O, N, C and B on the octahedral interstitial sites reduces the energy gap between the hexagonal-close-packed (HCP) and face-centered cubic (FCC) phases, thus assisting the formation of FCC-Ti under elevated temperature or plastic deformation. Such a gap further decreases with the increase in the interstitial content, which is consistent with the experimental observation of FCC-Ti under high interstitial content. The relative stability of the interstitial-containing HCP-Ti and FCC-Ti was studied against the physical and chemical origins, e.g., the lattice distortion and the electronic bonding. Interstitial O, N, C and B also reduce the stacking fault energy, thus further benefiting the formation of FCC-Ti.
