A Series of MAX Phases with MA-Triangular-Prism Bilayers and Elastic Properties

Hongxiang Chen; Dongliang Yang; Qinghua Zhang; Shifeng Jin; Liwei Guo; Jun Deng; Xiaodong Li; Xiaolong Chen

doi:10.1002/anie.201814128

A Series of MAX Phases with MA-Triangular-Prism Bilayers and Elastic Properties

Angew Chem Int Ed Engl. 2019 Mar 26;58(14):4576-4580. doi: 10.1002/anie.201814128. Epub 2019 Mar 3.

Authors

Hongxiang Chen^{1

2}, Dongliang Yang³, Qinghua Zhang¹, Shifeng Jin¹, Liwei Guo^{1

4

5}, Jun Deng^{1

6}, Xiaodong Li³, Xiaolong Chen^{1

6

7}

Affiliations

¹ Research & Development Center for Functional Crystals, Laboratory of Advanced Materials and Electron Microscopy, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
² School of Materials Science and engineering, Fujian University of Technology, Fuzhou, 350118, China.
³ Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049, China.
⁴ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
⁵ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
⁶ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China.
⁷ Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China.

PMID: 30729635
DOI: 10.1002/anie.201814128

Abstract

We report a new type of MAX phase (M=transition metals, A=main group elements, and X=C/N), Nb₃ As₂ C, designated as 321 phase. It differs from all the previous M_n+1 AX_n phases in that it consists of an alternate stacking of one MX layer and two MA layers in its unit cell, while only one MA layer is allowed in usual MAX phases. The new 321 phase exhibits a bulk modulus of Nb₃ As₂ C up to 225(3) GPa as determined by high-pressure synchrotron X-ray diffraction, one of the highest values among MAX phases. Isostructural 321 phases V₃ As₂ C, Nb₃ P₂ C, and Ta₃ P₂ C are also found to exist. First-principles calculations reveal the outstanding elastic stiffness in 321 phases. Among all 321 phases, Nb₃ P₂ C is predicted to have the highest elastic properties. These 321 phases, represented by a chemical formula M_n+1 A_n X, were added as new members to the MAX family and their other properties deserve future investigations.

Keywords: MAX phases; carbides; elastic constants; high pressure XRD; layered compounds.

Abstract

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