Synthesis and Characterization of Ti2(Al1-x, Snx)C MAX Phase Solid Solutions

Abstract

MAX phases belong to new family of ternary carbides and nitrides that bridges the gap between the physical and mechanical properties of metals and ceramics. MAX phases have high stiffness, are good thermal and electrical conductors, and have relatively low thermal expansion coefficients, like their binary carbide and nitride counterparts. However, they also have some properties that are more typical of metals, including relatively low hardness, machinability, good thermal shock and oxidation resistance, and damage tolerance. Published reports on the high temperature oxidation and creep resistances of Ti3SiC2 and Ti2AlC indicate that the MAX phases are good candidates for high-temperature applications, such as turbine disk coatings, nuclear fuel cladding, etc. However, it is not yet fully understood to what extent the properties of MAX phases can be tailored by solid solution substitutions or by controlling their microstructure. This research project focuses on the synthesis and characterization of Ti2(Al1-x, Snx)C MAX phase solid solutions, and the effects that alloying with Sn has on the microstructural characteristics and mechanical properties of Ti2AlC across the solubility range. Synthesis and characterization were performed using various processes and equipment, including spark plasma sintering (SPS), x-ray diffraction (XRD), scanning electron microscopy (SEM), resonant ultrasound spectroscopy (RUS), and Vickers hardness testing, among several refinement methods.