Kinetic role of Cu content in reaction process, behavior and their relationship among Cu-Zr-C system

Abstract

The influence of Cu content on the reaction process, reaction behavior and obtained products in the Cu-Zr-C system, as well as their relationships, were investigated. The results showed that ZrC was synthesized through the diffusion and dissolution of C into a Cu-Zr liquid. Increasing the Cu content enhanced the amount of Cu-Zr liquid formed at the early stage but decreased the amount of C atoms dissolving into the melt at unit time. Consequently, the ignition time initially decreased and then increased. Conversely, with an increased Cu content, the energy required for igniting the neighboring unreacted powders increased, while the heat released by the reaction and the dwell time of the compact at high temperatures decreased. These effects then resulted in the reduction of combustion wave velocity, combustion temperature and ZrC particle size. Furthermore, the synthesis of ZrC is a multistage process, which provides a nonuniform distributed ZrC particle size. The sub-μm ZrC particle reinforced Cu matrix composite was fabricated by adding a ZrC-Cu master alloy prepared through a self-propagating high-temperature synthesis reaction into liquid Cu.