The Effect of Equal Channel Angular Pressing on Friction Coefficients of Copper Samples in the Ring-Compression Test

In this research, the effect of fine-grained microstructure on the friction coefficient compared to the coarse-grained one in the ring-compression test of copper samples is investigated. The equal channel angular pressing process was performed on annealed copper at room temperature and in the B_c route in three consecutive passes. Then, the ring-compression test was carried out on the ring-shaped samples at room temperature and in three conditions: dry, with Molybdenum disulfide, and graphite lubricants with deformation rates of 12.5, 25, 37.5, 50, and 62.5%. The calibration curves were provided using the finite element method and analysis of variance was employed to investigate the effect of parameters on friction coefficients. The results showed that the friction coefficients in ECAPed copper in the first and second passes while using graphite and Molybdenum disulfide lubricants are similar. ECAPed copper in the third pass and annealed copper, respectively have lower friction coefficients when being lubricated with graphite and Molybdenum disulfide lubricants compared to other copper samples. Additionally, in all copper samples, except for ECAPed copper in the third pass, the Molybdenum disulfide lubricant decreased the friction coefficient more compared to graphite lubricant.