Regression Technique Research Of Cu-Ni-Si Alloy

Abstract:Cu-2.0Ni-0.34Si-Mg and Cu-5.0Ni-1.2Si alloys have been prepared using medium frequency induction furnace. Drawing lessons from aluminium alloy regression technique, we have designed a copper alloy regression technique.The electrical conductivity and micro-hardness of two alloys and the microstructure of alloy examined by using Optical Microscopy(OM) and Transmission Electron Microscopy(TEM) have been used to determine the parameters of copper alloy regression technique. The Influence of each step of the copper alloy regression technique has been studied on Cu-5.0Ni-1.2Si alloy. The main conclusion remarks are as follow:1. The results show the process parameters of retrogression heat treatment of Cu-2.0Ni-0.34Si-Mg:hot rolling and on-line quenching after4h solution at900℃+8h pre-aging treatment at600℃+80%cold rolling+regression of heat treatment. With the regression temperature no less than760℃and the holding time no less then2min, we obtained supersaturated solid solution.2. The micro-hardness and the related electrical conductivity of the regression Cu-2.0Ni-0.34Si-Mg alloy can be improved to180HV and60%IACS by16h salt bath aging treatment at450℃.3. The research obtained the process technology of Cu-5.0Ni-1.2Si: hot rolling and on-line quenching after4h solution at980℃,8h pre-aging at600℃+80%cold rolling+the regression of heat treatment. With the regression temperature no less than800℃and the holding time no less then2min, we obtained supersaturated solid solution.4. The micro-hardness and the related electrical conductivity of the regression Cu-2.0Ni-0.34Si-Mg alloy can reach its top to214HV and51.6%IACS after8h aging at450℃5. The main factors Influencing the result of the copper alloy regression technique:the regression temperature and whether there being cold rolling. Secondary factors:the state of copper alloy before pre-aging, the pre-aging temperature and the regression time. 6. Cold rolling devoted to grain refinement and solute atoms dissolving, which means higher micro-hardness and lower electrical conductivity.7. The regression temperature mainly devoted to solute atoms dissolving, so the higher regression temperature, the lower electrical conductivity.