Study on dynamic mechanical properties and constitutive model of B-10/Al composite compared with its matrix of high-purity aluminum

摘要

The dynamic mechanical properties of B-10/Al composite have been tested by split Hopkinson pressure bar. High-purity aluminum, the matrix of composite, has been tested as the comparison with B-10/Al composite. The scope of strain rate is from about 3000 s(-1)-12000(-1), and the temperature scope is from room temperature to 350 degrees C. The true strain-stress curves have been obtained. The sensitivity of strain rates and temperatures on the true stress of B-10/Al composite and high-purity aluminum has been analyzed. The true stress of the B-10/Al composite material is 50% higher than that of pure aluminum. The strain rate sensitivity of B-10/Al composite material is less than that of pure aluminum. The true stress of B-10/Al composite material drops obviously when temperature is higher than 250 degrees C, due to the interface fracture between particles and matrix, and the movement of boron particles. The adiabatic temperature rise due to material deformation has been calculated, considering the heat capacity with the various temperatures. The total temperature due to plastic deformation of the B-10/Al composite material is 41% higher than that of pure aluminum. The constitutive equations based on power-law and Johnson-Cook models have been introduced to characterize the dynamic mechanical properties of materials under different temperature and strain rates. The fitting results of the two constitutive models are compared with the experimental results. The fitting accuracy of the Johnson-Cook model is higher than that of pow-law model.