Experimental and DFT investigation of (Cr, Ti)3AlC2 MAX phases stability. Issue 3 (4th May 2017)

• Record Type: Journal Article
• Authors: Burr, Patrick A.; Horlait, Denis; Lee, William E.
• Is Part Of: Materials research letters. Volume 5:Issue 3(2017)
• Page Start: 144
• Page End: 157
• Publication Date: 2017-05-04
• Subjects: Quaternary MAX phase -- synthesis and characterization -- DFT simulations -- atomic ordering; Materials science -- Research -- Periodicals; Biomedical materials -- Research -- Periodicals; Composite materials -- Research -- Periodicals; Biomedical materials -- Research; Composite materials -- Research; Materials science -- Research; Periodicals; 620.1105
• DOI: 10.1080/21663831.2016.1222598
• Languages: English
• ISSNs: 2166-3831

Abstract

ABSTRACT: Using a synergistic combination of experimental and computational methods, we shed light on the unusual solubility of (Cr, Ti)3 AlC2 MAX phase, showing that it may accommodate Cr only at very low concentrations (<2 at%) or at the exact Cr/(Cr + Ti) ratio of 2/3, even when the ratio of reactants is far from this stoichiometry (1/2 ≤ Cr/(Cr + Ti) ≤ 5/6). In both phases, Cr exclusively occupies the 4f sites, bridging carbide layers with the Al layer. Despite this, the peculiar stability of (Cr2/3 Ti1/3 )3 AlC2 is attributed to the formation of strong, spin-polarized Cr–C bonds, which result in volume reduction and a marked increase in c/a ratio. GRAPHICAL ABSTRACT: IMPACT STATEMENT Solubility of Cr and Ti in (Cr, Ti)3 AlC2 was investigated using experimental and DFT techniques. It was also determined that (Cr2/3 Ti1/3 )3 AlC2 owe its remarkable stability to the formation strong Cr–C bonds.