Experimental Study On High Temperature Plastic Deformation Behavior And Hot Working Characteristics Of Copper Alloy

Cu6Ni6Sn alloy is a kind of Cu-Ni-Sn alloy,which belongs to the typical amplitude modulated decomposition and strengthening alloy.This copper alloy not only has good comprehensive mechanical properties,thermal processability and high oxidation resistance,corrosion resistance,is widely used in machinery manufacturing and national defense industry and other fields,especially in the engine important wear and corrosion resistance parts.Therefore,it is of great significance and practical value to study the hot deformation behavior and hot working characteristics of Cu6Ni6Sn alloy and optimize the forming process for engineering application.Based on Cu6Ni6Sn alloy in Gleeble-3800 thermal simulation testing machine for hot compression simulation experiment,study the alloy in the strain rate and temperature650?-850?,0.01-1s^-1within the scope of the high temperature deformation behavior,analyzes the deformation regularity of influence parameters on the microstructure of alloy and the backward extrusion of metal hot deformation process is simulated,for the alloy in the process of actual provide reasonable technical parameters and theoretical guidance.The main results are as follows:The flow stress curves of Cu6Ni6Sn alloy under different deformation conditions were obtained based on the thermal simulation compression test data.The change of flow stress with strain is the result of competition between the work hardening effect caused by dislocation proliferation and congestion and the dynamic softening effect caused by dynamic recovery and dynamic recrystallization.The flow stress of Cu6Ni6Sn alloy decreases with the increase of deformation temperature or the decrease of strain rate.The constitutive model of Cu6Ni6Sn alloy was established based on the experimental data of thermal compression simulation.The average relative error AARE is 5.28%,and the correlation coefficient R is0.992,which can better predict the flow stress under different deformation conditions.Based on the thermal processing diagram,the optimal processing parameters of Cu-Ni-Sn alloy are obtained from the temperature range of 730?-780?and the strain rate range of0.082s^-1-0.223s^-1.When the deformation temperature is slightly higher than 780?,the strain rate can be increased appropriately.When the deformation temperature is below 730?,the strain rate can be appropriately reduced.The hot deformation process of Cu6Ni6Sn alloy during reverse extrusion was numerically simulated by Deform-3D finite element software.The results show that the deformation temperature and strain rate have little influence on the equivalent strain,but have great influence on the equivalent stress,and the variation trend is similar to the conclusion of hot compression experiment.Therefore,the conclusion of hot compression experiment can provide theoretical basis and technological basis for plastic forming of alloy.