Extrusion Process And Parameter Optimization Of B₄C_p/Al Composites

B₄C_p/Al Composites have excellent mechanical properties.It can play an important role in aerospace,armor and other fields.However,the practical application of B₄C_p/Al Composites is insufficient due to the limitation of preparation technology in China.In order to optimize the preparation process,the hot compression experiment combined with finite element simulation is proposed to optimize the extrusion process parameters of B₄C_p/Al Composites,which has theoretical significance and practical reference value.In this paper,the hot reducing experiments of B₄C_p/6061Al composites with 20%volume fraction were carried out on Gleeble-3500 thermal simulator.The law of stress-strain curves for 20 sets of samples with strain rates of 0.001s^-1,0.01s^-1,0.1s^-1 and1s^-1 at 450?,475?,500?,525?and 550?were investigated,and the experimental data were frictionally calibrated.The results show that the flow stress of B₄C_p/6061Al composites increases with the increase of strain rate at the same temperature,and decreases with the increase of deformation temperature at the same strain rate;The friction factor has a great influence on the experiment.After calibration,the maximum difference of peak stress is 5.275MPa.The material constitutive equation is constructed by analyzing the basic theory of stress-strain constitutive equation and the stress-strain curve after friction calibration.The effects of extrusion temperature and extrusion speed on the preparation of B₄C_p/6061Al composites were investigated by finite element method.The simulation results were analyzed from the aspects of equivalent strain,equivalent stress and damage coefficient.The results of FEM calculation show that at 500?the extrusion pressure and damage of B₄C_p/6061Al composites is smaller.Equivalent strain and stress parameters are also reasonable.500?is more suitable for actual extrusion temperature than the other three temperatures.The extrusion force of B₄C_p/6061Al composites extruded at 1 mm/s extrusion speed fluctuates slightly,and the damage is minimal.Therefore,isothermal extrusion of B₄C_p/6061Al composites at 500?with 1mm/s extrusion speed is the optimum technology parameter.