Fabrication of Ti2AlC Compound by Mechanical Alloying and Spark Plasma Sintering and Investigation of Its Cyclic Oxidation Behavior

In this study, the Ti2AlC MAX phase was produced by mechanical alloying (MA) and spark plasma sintering (SPS) of a mixture of Ti, Al and C powders with a molar ratio of 2:1.1:1. The time of the mechanical alloying process and sintering process temperature were selected as variables, and their effect on the properties of resulted samples was investigated. SPS process was performed on the samples at temperatures of 1000, 1100 and 1200 degrees C and under the pressure of 30 MPa for 20 min. The cyclic oxidation behavior of the samples was then investigated. The density and hardness of the samples were also examined. The results showed that the best specimen had a density of 4.2 gr cm(-3) and a hardness of 995 HV. According to the x-ray diffraction patterns, it was found that the Ti2AlC MAX phase has been formed in all samples. The cyclic oxidation process was performed for 50 h on the selected sample at temperatures 1200 and 1350 degrees C. The results of oxidation test showed that Al2O3 and TiO2 oxide layers formed with good adhesion on the substrate surface. The weight gain equation of the oxidation test was obtained powerfully at temperatures of 1200 and 1350 degrees C, where the oxidation constant (k(o)) increased from 8 x 10(-4) to 9 x 10(-3) mg(n) h(-1), respectively. In this study, the best results were obtained by MA time of 24 h and then SPS process at the temperature of 1200 degrees C.