Effect of annealing treatment on the dry sliding wear behavior of copper

The effect of annealing on the wear behavior of commercial grade pure copper (Cu) was evaluated by performing unlubricated pin-on-disc wear tests of as–received and annealed samples under 0.1–10 kgf normal load. It was found that annealing at 800 °C for 24 h led to an increase of grain size of Cu from ~ 6.7 to ~ 15.3 µm and a decrease in hardness. Wear rates of both samples increased while the friction coefficients decreased with increasing normal load. Subsurface microstructure evolution and wear debris were characterized by high resolution electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) after wear tests. Dynamic recrystallization and abnormal subsurface grain growth were observed in both samples under high load. Finally, the effect of annealing on the microstructure evolution and wear resistance of Cu were discussed.