Synthesis and characterization of a new (Ti1-yCuy)2(Al1-xCux)C MAX phase solid solution

Abstract

New [Ti(1-y)Cuy]2[Al(1-x)Cux]C solid solutions have been synthesized by solid-state reaction performed at 760 and 800 °C on compacted Ti2AlC-40 vol % Cu composite particles produced by mechanical milling. Using XRD and EDXS, it is demonstrated that Cu atoms can enter the crystallographic structure of the Ti2AlC MAX phase, whereas a Cu(Al) solid solution is formed during thermal treatment. A selective chemical etching of the Cu(Al) matrix is performed to determine the composition of the MAX phase solid solution by analyzing the filtrate and the solid phase using ICP-OES end EDXS methods respectively. (Ti0.85Cu0.15)2(Al0.75Cu0.25)C and (Ti0.85Cu0.15)2(Al0.58Cu0.42)C solid solutions are formed after thermal treatment at 760 and 800 °C, respectively. The substitution rate on the A site of the MAX phase thus increases with temperature.