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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 °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 °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 °C, where the oxidation constant (ko) increased from 8 × 10–4 to 9 × 10–3 mgn 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 °C. [ABSTRACT FROM AUTHOR]

In the present investigation, friction stir processing (FSP) was used to integrate Ni particles into the surface of copper in order to fabricate a surface composite. Determining an optimized percentage of Ni particles, different dimensions of grooves were machined into the Cu plates. Then, the specimens' grooves were filled by nickel reinforcement particles, and friction stir process was performed on the specimens with tool rotation speed of 800 rpm and traverse speed of 50 mm/min. Optical microscope (OM) and scanning electron microscope (SEM) were used to evaluate the microstructure. Pin-on-disk test was performed to evaluate wear properties using pins manufactured from the FSPed zone. Also, Micromet-Buehler Vickers hardness tester was used to test the FSPed surfaces' microhardness. The results show that the best properties are obtained when using 2 × 2 mm groove. In this situation, microhardness and wear properties were improved as 40% and 60% compared to the substrate, respectively. [ABSTRACT FROM AUTHOR]