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Journal of Advanced Ceramics

Authors

Qiang XU, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
Yanchun ZHOU, Science and Technology on Advanced Functional Composite Laboratory, Aerospace Research Institute of Materials & Processing Technology, Beijing 100076, China
Haiming ZHANG, Science and Technology on Advanced Functional Composite Laboratory, Aerospace Research Institute of Materials & Processing Technology, Beijing 100076, China School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
Anna JIANG, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
Quanzheng TAO, Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
Jun LU, Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
Johanna ROSÉN, Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
Yunhui NIU, State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
Salvatore GRASSO, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
Chunfeng HU, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China

Keywords

V2SnC, new MAX phase compound, crystal structure, first-principles calculations

Abstract

Guided by the theoretical prediction, a new MAX phase V2SnC was synthesized experimentally for the first time by reaction of V, Sn, and C mixtures at 1000 ℃. The chemical composition and crystal structure of this new compound were identified by the cross-check combination of first-principles calculations, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and high resolution scanning transmission electron microscopy (HR-STEM). The stacking sequence of V2C and Sn layers results in a crystal structure of space group P63/mmc. The a- and c-lattice parameters, which were determined by the Rietveld analysis of powder XRD pattern, are 0.2981(0) nm and 1.3470(6) nm, respectively. The atomic positions are V at 4f (1/3, 2/3, 0.0776(5)), Sn at 2d (2/3, 1/3, 1/4), and C at 2a (0, 0, 0). A new set of XRD data of V2SnC was also obtained. Theoretical calculations suggest that this new compound is stable with negative formation energy and formation enthalpy, satisfied Born-Huang criteria of mechanical stability, and positive phonon branches over the Brillouin zone. It also has low shear deformation resistance c44 (second-order elastic constant, cij) and shear modulus (G), positive Cauchy pressure, and low Pugh’s ratio (G/B = 0.500 < 0.571), which is regarded as a quasi-ductile MAX phase. The mechanism underpinning the quasi-ductility is associated with the presence of a metallic bond.

Publisher

Tsinghua University Press

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