Behavior And Phase Equilibria Of Cu-Zn-Se Ternary Interdiffusion

Lead brass is widely used in various shapes machining parts because of its excellent properties such as cold and hot processing, cutting and resistance of wearing,which is recognized as a kind of the important basal materials around the world. It is found that the Lead in the lead brass is harmful by the scientific research,but the cutting properties of the free-lead brass is not satisfactory so that cannot be used in the precision machined production.therefor,it is important to adopt other elements rather than lead in the brass so as to make the properties approximate to the lead brass that can meet the needs in the industry.From a lot of scientific researches on the environment-friendly brass that use the Bismuth instead of Lead in the research group recent years,It was found that the properties of cutting,mechanical,resistance of wearing and corrosion of the brass that with the coaction of Bismuth and Selenium approximates to the lead brass.Though,the stability of cutting property of the lead-free brass that content Bismuth and Selenium is not satisfying, possibly due to the characteristics of Selenium such as low melting point, easy oxidation and uncertain existing form in the brass. the composition and microstructure of equilibrium phases of Cu-Zn-Se this three kinds of elements in different temperature and durations of heat preservation were researched by combining with experimentation and calculation. The specific processes are as followes:1) It showed that the process of the diffussion reactiones is not obvious at relative low temperature and short time by the dynamics model of diffusion,but the diffusion layer will be thicker with temperature elevating obviously:the diffusion rate of Cu/Se is much faster than Zn/Se in the process of diffusion reaction;the thickness of diffusion thickened very slowly at low temperature when time was prolonged; the influence of the different durations of heat preservation on the thickness of diffusion layer is more obvious.In additionally, when the temperature reaches200℃, It can be see that the diffusion layer of Cu2Se will appear next to the diffuse interface of the Cu/Se diffusion layer.2) The diffusion reactiones between Copper and Selenium, Zinc and Selenium can be observed at the same time in the deffusion process of H62/Se at low-temperature short time heating. The diffusion rate of Cu/Se is much faster than Zn/Se,but the diffusion-solution layer of Zn/Se was so compact that can blocked the reaction of Cu/Se;The stability of the compound of Zn/Se is better than Cu/Se.3) The equilibrium phase of the alloy contains the compounds of Cu2Se、CuSe and ZnSe in the equilibrium reaction of Cu-Zn-Se at high temperature when the content of Selenium is high and Zinc is low. The main equilibrium phase is ZnSe when the content of Selenium is low and Zinc is high; the excess Zinc can react with the Copper to form the equilibrium phase of brass. The results showed that Selenium react mainly with Zinc to form the compound of ZnSe when the content of Selenium is very low in Cu-Zn-Se alloys.4) The most stability phase and component are analyzed by the model of Reaction, Equilib and Phase Diagram of the FactSage, which provided a contrast for the result of experiment. The result showed that the equilibrium phase of theoretical basically coincide with the experimental.