Microstructure and mechanical properties of Cu–Cr–Zr–ZrB2 composites by novel fabrication process of ultrasonic vibration treatment

Abstract

Copper matrix composites with dual-scale particles were fabricated through casting with reaction. Ultrasonic vibration has been successfully introduced into the melt at about 1523 K while the microstructural development and mechanism of copper matrix composites with high-performance through a novel method of casting with ultrasonic vibration treatment are investigated. When ultrasonic vibration is applied, the distribution of micro-scale particles is greatly improved. Primary Cr phase convents to non-dendrite and large aggregates of ZrB2 particles are disrupted into small clusters because of acoustic cavitation and acoustic streaming. The ultimate tensile strength and elongation of Cu-1wt%Cr-0.3 wt%Zr-1wt%ZrB2 composite in as-cast state were 321 MPa and 14.37 %, recording a 28.4 % and 14 % increment respectively compared with the sample without treatment. After solution treatment, deformation and aging subsequently, the uniform distribution of reinforcements also decreases the average transverse grain thickness and increases the dislocation density which improve the comprehensive properties.