To determine the relationships between operating conditions and tribological properties of Zn-30Al-3Cu alloy, its wear characteristics were investigated at wide ranges of oil flow rate, pressure and sliding velocity using a block-on-disk type test apparatus. The results are compared to those of SAE 660 leaded bearing bronze. Wear loss of these materials increased with sliding distance, pressure and sliding velocity, but decreased slightly with oil flow rate. The relationships between operating conditions and lubricated wear properties of Zn-30Al-3Cu alloy were determined by nonlinear regression analysis of the experimental data. Lubricated wear behavior of the zinc-based alloy was discussed in terms its microstructure and mechanical properties, and test conditions.

This study fabricated a WC/T-800 cermet coating layer with Co-Mo-Cr (T-800) powder and WC powder using laser cladding, and analyzed its microstructure, hardness and wear properties. For comparison, casted bulk T-800 was used. Laser cladded ­WC/T-800 cermet coating layer showed circular WC phases in the Co matrix, and dendritic laves phases. The average laves phase size in the cermet coating layer and bulk T-800 measured as 7.9 µm and 60.6 µm, respectively, indicating that the cermet coating layer had a relatively finer laves phase. Upon conducting a wear test, the cermet coating layer added with WC showed better wear resistance. In the case of laser cladded WC/T-800 cermet coating layer, abrasion wear was observed; on the contrary, the bulk T-800 showed pulled out laves phases. Based on the above findings, the WC/T-800 cermet coating layer using laser cladding and the relationship between its microstructure and wear behavior were discussed.

In the present study, the mechanical properties and high-temperature sliding wear behaviour of the Al6082-SiC-TiO2 hybrid composite in different environmental conditions produced by the stir-casting process were investigated and distinguished with single-reinforced composites (Al6082-SiC and Al6082-TiO2) and matrix alloy. The microstructure of composites exhibited a reasonably uniform scatter of particles in the aluminium matrix with good bonding between the matrix-particle interfaces. The hybrid composite’s hardness and ultimate tensile strength showed higher hardness and tensile strength than matrix alloy and single-reinforced composites, whereas trends were reversed for the elongation. The impact test of the materials was conducted at different temperatures (room temperature, 0°C, –25°C, –50°C, and –75°C). The hybrid composite shows higher impact strength than the other materials, and impact strength decreases with temperature because ductility decreases with temperature. The fracture surfaces were examined to identify the fracture mechanism. The sliding wear test was conducted at different temperatures (room temperature, 100°C, 175°C, 250°C and 325°C) to distinguish the tribological behaviour of materials. The weight loss of the materials was increased with an increase in temperatures. The hybrid composite shows a lower weight loss than the other condition samples, irrespective of the temperatures. The wear surfaces were examined to predict the material removal mechanism.