The microstructures and properties of in-situ ZrB2 reinforced Cu matrix composites

Abstract

In this work, ZrB2 particles have been in-situ synthesized in the Cu melts using Cu-B master alloy as the starting material. It is found that the non-uniformly distributed ZrB2 particles in the prepared as-cast composites tend to aggregate into agglomerations and this trend is more pronounced with the ZrB2 content increasing.In addition, the size of hexagonal plate-like ZrB2 whose diameter ranges from less than 1 μm to more than 10 μm accompanied by the thickness ranging from about 0.5 μm to 2 μm shows an uneven appearance. The increasing ZrB2 contents can give rise to the higher hardness values of 160–205% of the original pure Cu. However, the electrical conductivity which is about 52.9% IACS to 76.8% IACS will be severely affected. Besides, the decreased friction coefficient from 0.6 to 0.4 and the gradually declining lost mass of the samples indicates the better wear resistance property with increasing ZrB2 contents.