Effect of La addition on the particle characteristics, mechanical and electrical properties of in situ Cu-TiB2 composites

In situ Cu-TiB2 composites can be synthesized via metallurgical process by mixing Cu-B and Cu-Ti master alloys before casting. In this paper, La, as a rare earth element was added to the composites to improve the comprehensive properties and the effects of its addition on the microstructures, mechanical and electrical characteristics of Cu-TiB2 composites were investigated. Results show that addition of La significantly diminishes the average size and facilitates a homogeneous distribution of TiB2 particles in the copper matrix. As a result, an improvement in mechanical properties was achieved. In particular, a remarkable change in the conductivity of the composites appears with the variation of La content. The mechanisms of particle refinement and improvements in properties by La alloying were analyzed. (C) 2016 Elsevier B.V. All rights reserved.