Reaction behavior and formation mechanism of ZrC and ZrB2 in the Cu–Zr–B4C system

• The heating rate could not greatly affect the phase evolution path and DSC products.
• Solid-state reaction between Zr and B4C is one formation mechanism of ZrC and ZrB2.
• Replacement reaction between B4C and Cu–Zr melt is a formation mechanism of ZrC–ZrB2.
• The addition of Cu to Zr–B4C reactants promotes the full conversion of ZrC and ZrB2.
• Cu can alter the reaction route of Cu–Zr–B4C system by forming various Cu–Zr phases.

In this work, the formation mechanism of ZrC and ZrB2 in the Cu–Zr–B4C system was studied by differential scanning calorimeter and X-ray diffraction. Moreover, the effect of heating rate on the reaction behavior was also investigated. The results revealed that the heating rate did hardly influence the reaction process and product in the range of 10–30 °C/min. The formation mechanism of ZrC and ZrB2 in the Cu–Zr–B4C system could be ascribed to the solid-state reaction between Zr and B4C particles, and the replacement reactions of B4C with the Cu–Zr liquid and copper zirconium compounds. The addition of Cu in the Cu–Zr–B4C reactants can change the phase evolution route via producing various Cu–Zr intermediate phases and promote the formation of ZrC and ZrB2.