Ab initio study of the structure, elastic, and electronic properties of Ti3(Al1\u2212nSin)C2 layered ternary compounds

S T Ahams,N F Abdul Pattah,A Shaari,R Ahmed,M C Idris,B U Haq

doi:10.1038/s41598-021-84466-5

S T Ahams, N F Abdul Pattah + Show 4 more

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https://doi.org/10.1038/s41598-021-84466-5

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Abstract

The MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years. Here, we present a systematic investigation of the electronic, structural stabilities, and elastic properties of Ti3(Al1−nSin)C2 (n = 0,1) MAX phase materials using the ab initio method via a plane-wave pseudopotential approach within generalized-gradient-approximations. The computed electronic band structures and projected density of states show that both Ti3SiC2 and Ti3AlC2 are metallic materials with a high density of states at the Fermi level emanating mainly from Ti-3d. Using the calculated elastic constants, the mechanical stability of the compounds was confirmed following the Born stability criteria for hexagonal structures. The Cauchy pressure and the Pugh’s ratio values establish the brittle nature of the Ti3SiC2 and Ti3AlC2 MAX phase materials. Due to their intriguing physical properties, these materials are expected to be suitable for applications such as thermal shock refractories and electrical contact coatings.

Highlights

The MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years
In the early 1960s, the majority of MAX phases were discovered in a succession of experiments by Nowotny and his co-workers[7]
Based on the web of science (WOS)[12], to date, there are over 4,168 published papers on MAX compounds alone, with Ti3SiC2 having roughly half of the published works in the past six years[13,14]

Summary

Introduction

The MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years. The Cauchy pressure and the Pugh’s ratio values establish the brittle nature of the Ti3SiC2 and Ti3AlC2 MAX phase materials Due to their intriguing physical properties, these materials are expected to be suitable for applications such as thermal shock refractories and electrical contact coatings. The MAX phases such as Ti3SiC2 and Ti3AlC2 are a 312 class of layered ternaries where the individual phases differ by the number of M-layers parting the A-layers in the 312-MAX phases[17,18,19,20,21] These compounds combine some characteristics of metals like strong compressive strength, high fracturing strength, hardness, ductility, good electrical and thermal conductivity, high stiffness, damage tolerance, relatively low thermal expansion coefficient. Analogous facts have been noticed in the temperature range 1473–1673 K in bulk T i3SiC2 in the hydrogen atmosphere and it was found that the dissociation of T i3SiC2 was accelerated by h ydrogen[37]

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