Copper Matrix Hardening by Alumina Particles :: Total ...
The increases in microhardness were assumed to be due to the uniformly distributed alumina particles and small grain size of the copper matrix. Figure 1: Distribution of alumina particles in the Cu+4mas% Al 2 O 3 copper matrix after different milling time: a) 3h, b) 5h, c) 10h, d) 20h.