Anharmonicity of the lattice vibration in shape memory alloys: quantitative analyses based on first-principles calculations

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K18228
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kyoto University
• Principal Investigator: Ikeda Yuji 京都大学, 大学院工学研究科, 特定助教 (90710450)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 形状記憶合金 / 第一原理計算 / 格子振動（フォノン） / 不規則合金

Outline of Final Research Achievements

We formulate and implement a first-principles-based method to analyze the lattice vibration in disordered alloys to elucidate the lattice vibrational properties of shape memory alloys with nonstoichiometric composition ratios and its contribution to the order-disorder transition. We apply this method to various models of disordered alloys including high-entropy alloys and found characteristic behaviors in their phonon spectra such as peak broadening and peak discontinuity. We also found from the analysis on magnetic disordered alloys that the phonon spectra largely depend on the magnetic states of the alloys. We furthermore analyze the force constants in disordered alloys in detail and elucidate its dependences on element-pairs and on interatomic distances.

Free Research Field

計算材料科学