Study On Dynamic Compressive Mechanical Response And Microstructure Evolution Of 2524 Aluminum Alloy

Aluminum alloy materials are widely used in aerospace and automotive lightweight materials.They often need to bear dynamic compressive load in actual service conditions.Therefore,it is necessary to study the dynamic compressive mechanical properties and microstructure evolution of aluminum alloy materials in order to better guide the engineering application.Among the aluminum alloy materials for aviation,Al-Cu-Mg alloy has excellent room temperature strength,toughness,fatigue resistance and fracture toughness,so it has become an important structural material for key parts such as aircraft skin and wall panel.In this paper,2524-T3 aluminum alloy is selected as the research object,and the dynamic compression test of 2524-T3 aluminum alloy under different temperature and strain rate is carried out by using the separated Hopkinson pressure bar device.The dynamic mechanical properties and microstructure transformation mechanism of 2524-T3 aluminum alloy are analyzed.Research findings:(1)Under quasi-static compression load and dynamic compression load,2524-T3 aluminum alloy shows strain hardening effect.In the range of room temperature～150℃,the strain hardening index is negatively correlated with temperature and negatively correlated with strain rate.In the range of 200～400℃,the strain hardening index is positively correlated with temperature.The strain hardening index first decreases and then increases with the increase of strain rate.In addition,2524-T3 aluminum alloy shows strain rate strengthening effect.Under the condition of 500～3000 s-1 strain rate,the plastic deformation mechanism is still dominated by dislocation thermal activation mechanism.The yield strength increases with the increase of strain rate and decreases with the increase of temperature.However,at 200℃,the yield strength of 2524-T3 aluminum alloy is significantly higher than that at other temperatures due to the precipitation of the second phase.(2)The modified JC constitutive model of 2524-T3 aluminum alloy is established:This model is in good agreement with the measured stress-strain data of 2524-T3 aluminum alloy.(3)Under the dynamic compression load of room temperature～200℃,the adiabatic shear sensitivity of 2524-T3 aluminum alloy increases with the increase of temperature.2524-T3 aluminum alloy is prone to adiabatic shear phenomenon of plastic deformation and high localization.When the temperature is higher than 200℃,the thermal softening effect is enhanced,and the adiabatic shear phenomenon of aluminum alloy no longer appears.