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Prediction of New Structure, Phase Transition, Mechanical, and Thermodynamic Properties of Nb3Si
Author(s) -
Pan Yong
Publication year - 2017
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201700099
Subject(s) - materials science , tetragonal crystal system , phase transition , phase (matter) , niobium , thermodynamics , type (biology) , material properties , brittleness , structure type , crystal structure , crystallography , condensed matter physics , metallurgy , composite material , chemistry , ecology , physics , organic chemistry , biology
Although Nb‐based silicides are promising high temperature materials, the high temperature application of Nb‐based silicides is markedly influenced by Nb 3 Si phase. However, the structure and relevant properties of Nb 3 Si are not completely clear. To solve these problems, in this paper, we systematically investigate the structure, elastic properties, brittle or ductile behavior, and thermodynamic properties of Nb 3 Si based on the first‐principle calculations. Additionally, phase transition of Nb 3 Si under high pressure is studied in detail. The calculated results show that two new Nb 3 Si phases: Br 3 Sm‐type (space group: Cmcm, No.63) and Sc 3 In‐type (space group: P63/mmc, No.194) are predicted. Although Nb 3 Si with Ta 3 Si‐type is the most stable structure, pressure leads to phase transition from Ta 3 Si‐type structure to V 3 Si‐type structure at ≈60 GPa. We further demonstrate that Nb 3 Si is a ductile material. Importantly, we find that the heat capacity of Nb 3 Si with tetragonal structure is about 190 J (mol K) −1 , which is two times larger than that of other structures.