Study On Hot Deformation Behavior Of Cu-Ni-Sn Alloy

Cu-Ni-Sn alloy has become a key material for manufacturing high-performance sliding bearings because of its high thermal stability,strong fit and corrosion resistance.However,due to the particularity of the metal elements in the alloy and the wide range of alloy crystallization temperature,the selection of processing parameters during hot working has become the key to obtaining the best structure and properties of the alloy.Therefore,studying the thermal deformation behavior of Cu-Ni-Sn alloy has important engineering application value to improve the mechanical properties of the alloys,and thus the reliability of sliding bearings.This thesis takes Cu-Ni-Sn alloy as the research object and conducts thermal compression test based on Gleeble-3800 thermal simulation test machine.By collecting stress-strain data,the deformation temperature of Cu-Ni-Sn alloy is 650℃～850℃,and the strain rate is 0.001 s^-1～1 s^-1 flow stress curve characteristics and dynamic recrystallization behavior.The author discusses the effects of strain rate and deformation temperature on the microstructure evolution and rheological behavior of the alloy.Based on the Arrhenius constitutive relationship,the peak stress constitutive equation of the Cu-Ni-Sn alloy is obtained,and the predicted value is compared with the experiment to verify its validity.With the help of Deform3D software,a numerical simulation of the hot compression deformation process of the Cu-Ni-Sn alloy is carried out,and the distribution law of stress and strain and detailed changes under different deformation conditions are obtained.Finally,the rheological instability criterion and the dynamic material model are used to acquire the hot processing diagrams of the alloy under different deformation requirements,and determine the instability zone,the safe zone and the optimal processing parameter range of the Cu-Ni-Sn alloy high-temperature plastic deformation.The metallographic structure observation verifies the validity of the thermal processing map.The research results indicate that with the decrease of the strain rate and the increase of the deformation temperature,the flow stress value of the Cu-Ni-Sn alloy gradually decreases,indicating that the Cu-Ni-Sn alloy is a sensitive material of positive strain rate;Based on the Arrhenius relationship,the average relative error of the constitutive equation of the Cu-Ni-Sn alloy is 5.07%;with the decrease of the strain rate and the increase of the deformation temperature,the equivalent stress gradually decreases,and the equivalent strain of the Cu-Ni-Sn alloy gradually increases;The optimal processing parameter range of Cu-Ni-Sn alloy is:temperature 770℃～850℃,strain rate 0.0013s^-1～0.032s^-1.