In this work, the effect of 800 °C and 1100 °C post-heat treatment on the plasma spraying of Ti–Si–C–xMo (x = 1.0, 1.5) composite coatings was investigated. The composite coatings were composed of TiC, Ti3SiC2, Ti5Si3 and Mo5Si3 reacted phases. After heat treatment, the Ti3SiC2 and Mo5Si3 phases increased. The coating microhardness decreased by 16% and 18% for Ti–Si–C–1.0Mo and Ti–Si–C–1.5Mo coatings, respectively, after heat treatment at 1100 °C. Fracture toughness increased by 16% for the Ti–Si–C–1.5Mo coating after heat treatment at 1100 °C, which was mainly due to the heat treatment promoting Ti3SiC2 formation, healing micro-cracks, reducing the internal stress and making the microstructure dense. The coating friction coefficient before and after heat -treatment was between 0.4 and 0.6. After heat treatment, the wear amount of the coating was first reduced and then increased, and the minimum wear loss occurred after heat treatment at 800 °C. The wear mechanism was mixed abrasive wear, adhesive wear and tribo-oxidation wear.
Graphene-reinforced aluminium composites have been widely studied due to their excellent mechanical properties. However, only a few studies have reported their dynamic compression properties. The purpose of this study is to investigate the quasi-static and dynamic compression properties of graphene-reinforced aluminium composites. The addition of graphene improved the compressive stress resistance and energy absorption capacity of the aluminium matrix. An aluminium-0.5 wt.% graphene composite exhibited good compressive properties due to the different interfacial wave impedance generated by the additional grain boundaries or Aluminium-Graphene interfaces.
24 July 2023 in Journal of Materials Engineering and Performance
In this work, the TiC-reinforced CoNi alloy coatings were prepared by the plasma spraying method. Their microstructure, high-temperature oxidation, and thermal shock resistance at 900 °C were studied. The results showed that the CoNi alloy coating exhibited a single phase (c-Co-Ni-Cr-Mo). After adding Ti-graphite mixed powders, the sprayed coating exhibited TiC and TiO2 phases, besides the c-Co-Ni-Cr-Mo matrix phase. For CoNi alloy coating, the main oxidation products were Cr2O3 and CoCr2O4 (NiCr2O4). For TiC-CoNi alloy coating, the main oxidation products were the TiO2 phase, coupled with Cr2O3 and CoCr2O4 (NiCr2O4) phases. The content of oxides increased with the oxidation time. The oxidation weight gain of the TiC-CoNi composite coating was slightly higher than that of the CoNi alloy coating. The formation of TiC could improve the thermal shock resistance of the CoNi alloy coating.