Study On Preparation By Spark Plasma Sintering Method And Properties Of Cu-Zr-AIN Composite

Particle reinforced copper matrix composite possesses fine electrical conductivity and thermal conductivity, and its strength and hardness and other properties can be also improved with mixing. Among different types of particles, AlN particle has a high melting point, high hardness, low thermal expansion coefficient, which make AlN reinforced copper matrix composites more and more interesting.In this paper, the Cu, Zr and AlN powders were taken with a certain proportion. And after being milled for a specific time, the composite powders were taken to be analyzed by SEM, XRD and particle size analysis methods. And the properties of Cu-Zr-AIN composite powders under different ball milling time were studied. Then Cu-Zr-AIN composites were prepared by spark plasma sintering method. The microstructure was observed by metallographic microscope, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). The effects of sintering temperature and AlN content on the density, compressive strength, hardness, electrical conductivity and friction property of Cu-Zr-AIN composites were studied.The diffraction peak intensity of Cu and Zr was decreased with the increasing of milling time. The diffraction peak was broadened and the grain size was refined. During the process of milling, some Zr dissolved into Cu, and Cu/Zr over saturated solid solution was formed. After 20 hours, the new phase CusZr3 was formed. After 30 hours, Zr peak has been significantly weakened, and after 40 hours, the Zr peak disappeared. The diffraction peak of AlN was existing and its intensity changed little, which indicated that the AlN was steady during the process of ball milling. The average particle size of the composite powder decreased with the increasing of milling time. The size of the composite powder was 4.956um after being milled 30 hours. The size of the composite powder increased, when the milling time was extended. Through the experimental analysis, the optimal milling time of the composite powder was 30 hours.Cu-Zr-AIN composites were sintered by spark plasma sintering. With the increase of sintering temperature, the relative density of Cu-Zr-AIN composite gradually increases. When the sintering temperature was 800℃, the microstructure of the composite was uniform. When the sintering temperature is higher than 800℃, the density of composite increases slowly. The micro-hardness and compressive strength of composite increased gradually with the increasing of the sintering temperature between 700℃ and 800℃. But the micro-hardness and compressive strength of the composite decreased with the increasing of the sintering temperature, when the sintering temperature was over 800℃. So the optimum sintering temperature was 800℃.With the increasing of AlN content, the density, relative density and electrical conductivity of the composite were decreasing, while the micro-hardness and compressive strength show the trend of increase first and then decrease. With the increase of AlN content, the friction coefficient of the composite decreased first, and then increased. When AlN content was 5%, the friction coefficient decreased obviously. When the content of AlN was over 5%, the friction coefficient of the composites increased gradually. With the increase of AlN content, furrows generated by friction were shallow. And the peeling sheets of tissue are decrease, the wear surface of composite becomes smooth to delay the onset of severe wear.This paper was to explore preparation technology of Cu-Zr-AIN composite prepared by SPS, in order to prepare the copper matrix composites with high strength and high conductivity.