Evaluation of mechanical and wear properties of potassium acid titanate whisker-reinforced copper matrix composites formed by hot isostatic pressing

Copper matrix composites, in which copper powders are reinforced by potassium acid titanate whiskers, were formed by hot isostatic pressing. Two powder sizes (average diameters, 30 mu m and 250 mu m) were employed. The effects of the copper powder size, whisker content and strain rate on the tensile properties were studied. The wear properties were investigated by changing the normal load and sliding speed. Numerous whisker clusters were present in the copper matrix of the composites. For the 250 mu m copper powder, the ultimate tensile strength of the composite was not increased significantly by blending with the whiskers. For the 30 mu m copper powder, a uniform distribution of up to 5 wt.% whisker content enhanced the tensile strength. For pure copper and the composite containing 5 wt.% whiskers, the tensile strength increased with the strain rate. However, for composites with high whisker content, the tensile strength decreased at high strain rates. The wear volumes of the composites were nearly proportional to the sliding distance. Debonded whiskers promoted severe wear of the composites. It was confirmed that, if the abrasive wear is constrained under low applied load and slow sliding speed, potassium acid titanate whiskers provide an effective reinforcement and improve the wear resistance of the composites.