The effects of applied load, sliding speed & temperature on the wear behavior of pure M50
alloy steel (M sample) and M50 reinforced with 10 wt.% Al2O3 (MA sample) & M50 hybrid
reinforced with Al2O3 and graphene (MAG sample) were studied. The powders were mechanically
mixed and sintered by spark plasma sintering (SPS) technique under Argon
atmosphere at 1000 C for 5 min under 35 MPa pressure. The sample surfaces were mechanically
prepared to study the wear & friction behaviors via applying mechanical polishing
using 0.05 mm diamond pastes and 1200 grit emery papers to enhance the surface
roughness. The phase structure and microstructure were estimated using XRD, Electron
Probe Micro-Analysis (EPMA, JAX-8230) and Energy Dispersive Spectroscopy (EDS, GENESIS
7000). The hardness and density of all samples were investigated according to HVS-1000
Vickers’ hardness test and Archimedes’ principles, respectively. Friction and wear tests
were carried on a high-temperature pin-on-disk tribometer (HT-1000). The investigated
samples were cut into disk-shaped specimens with 8 mm thickness and 25 mm diameter.
Then, the prepared specimens were sliding against silicon nitride (Si3N4) balls. The samples
were exposed to four different loads (2, 5, 8, and 11 N). Also, four different sliding speeds
(0.18, 0.36, 0.54, and 0.72 m/s) was performed at room temperature (RT). Another group of
samples were tested at constant applied load of 11 N and constant sliding speed of 0.72 m/s
for four different temperatures (RT, 150, 300, and 450 C). MAG exhibited enhanced tribological
properties compared with M and MA thanks to the synergic action between Al2O3