Delamination Wear of Dispersion-Hardened Alloys

In order to investigate the effect of hard incoherent dispersoids on the sliding wear rate of dispersion-hardened alloys, internally oxidized Cu-Cr and Cu-Si alloys were tested. OFHC copper and oxygen doped OFHC copper were also used to compare their wear properties with dispersion-hardened alloys. The results of unlubricated wear tests at room temperature in the load range 2.22–22.2 N (0.5–5.0 lb) at a sliding speed of 3 × 10⁻² m/s show that the wear rate is linearly proportional to the normal load. Hard oxide dispersion strengthened alloys exhibited larger wear rates than the soft OFHC copper. Surface and subsurface observations indicate that wear was primarily due to crack nucleation, propagation, and delamination of wear sheets. The wear resistance of the materials decreased with increase in volume fraction of the oxide even when the hardness was increased. It is concluded that because of the immediate debonding between the matrix and the oxide particle, upon plastic deformation of the matrix, crack propagation is the wear rate controlling mechanism in these internally oxidized metals. The results, which are contrary to the prediction of the adhesion theory of wear, are consistent with the delamination theory.