Structural stability, mechanical property and phase transition of the Ti–H system

✍ Scribed by C.P. Liang; H.R. Gong

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 591 KB
• Volume: 35
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2010.07.074

✦ Synopsis

First-principles calculation reveals that the hexagonal close-packed (HCP) TieH phases are energetically more favorable than corresponding body-centered cubic (BCC) and facecentered cubic (FCC) phases when 0 H/Ti < 0.26, while the FCC phases become relatively more stable when H/Ti ! 0.26. Calculation also shows that H concentration has different effects on mechanical properties of HCP, BCC, and FCC TieH phases, and at a certain H concentration, the FCC phase is the most brittle with the biggest shear and Young's moduli among the calculated structures. Moreover, it is found that the H location plays an important role in phase transitions, i.e., the TieH phases with H at octahedral (O) and tetrahedral (T) sites would follow the Zener's and Burgers' mechanisms of the BCCeHCP phase transition, respectively, and the H at O and T sites could make the BCC / FCC transition along the Bain path easier and harder, respectively. The calculated results are compared with available experimental results in the literature and the agreements between them are fairly good.