The Research Of Preparation Process And Performance Of The Cu-Cr₂Zr Composite Materials

Owing to its excellent mechanical properties and electric conductivity, dispersion-strengthening copper-based composite materials have broad prospect of application, but now the existing copper-based materials also can't meet the requirements of the rising technology for the materials' performance, therefore, the development of new type copper-based material is urgently needed. The method of mechanical ball milling, as a kind of preparation method of dispersion-strengthening composite powders, can make reinforcing phase dispersed and well-distributed, then, greatly improve the mechanical properties of materials, as a result, in this paper, Cr2Zr alloy was prepared first by argon protection melting furnace, then Cr2Zr alloy was milled into Cr2Zr powders, Cu-Cr2Zr composite powders were prepared by mechanical alloying after that, finally Cu-Cr2Zr composite materials were prepared by vacuum hot-pressing sintering. Through the analysis of X-ray diffraction peak, the change of the grain size, the lattice distortion, the lattice constant and the deformation characteristics of the powder in the ball milling process, the process features and properties of the Cu-Cr2Zr composite powders were discussed by the method of ball milling; through the test of the mechanical properties and physical performance, the influence of the sintering process parameters and the composition of the Cr2Zr on the organization structure and performance of the Cu-Cr2Zr composite materials were discussed.The results of the reserach show that:(1)After melted for five times, Cr2Zr alloy can get pure CrZr Laves phase and its micro-hardness can reach 526.36Hv.(2)With the increase of the milling time, the diffraction intensity of the Cr2Zr powders gradually decreased, and the diffraction peaks of the Cr2Zr powders were gradually wide. When the milling time was less than 30h, the grain size and the lattice strain gradually increased;when the milling time was further increased, the grain size of the Cr2Zr powder continued to decrease, just the trend of the decrease of the grain size was gradually gentle, but the lattice strain began to decrease.(3)With the increase of the milling time, the grain size of the Cu-Cr2Zr composite powders was continuously detailed, and the diffraction peaks of Cu-Cr2Zr composite powders were gradually wide, but the diffraction intensity of the Cu-Cr2Zr composite powders gradually decreased;after 8 hours of milling, the diffraction peaks of the Cr2Zr in Cu-10%Cr2Zr composite powders disappeared completely, because Cr2Zr particles were completely wrapped in Cu matrix.(4) With the extension of the sintering time, the micor-hardnesses and flexural strengths of the copper-based composite materials gradually declined, but conductivity was improved; with the increase of the composition of Cr2Zr, the micro-hardnesses and flexural strengths of copper-based composite materials were gradually increased, but conductivity was decreased; with the increase of the sintering temperature, the micro-hardnesses and flexural strengths of copper-based composite materials increased first, then decreased, but conductivity was improved.(5)The densities and relative densities of the Cu-10%Cr2Zr composite materials were improved with the increase of the sintering temperature and sintering time, but reduced with the increase of the component of the Cr2Zr.(6)When the sintering temperature and the sintering time of the Cu-10% Cr2Zr copper-based composite materials are respectively 950℃and 2 h, it's electric conductivity, bending strength and relative density reach 78.6% IACS,1082.37MPa and 96.4% respectively, the comprehensive performance of the Cu-10% Cr2Zr composite materials is optimal.