Abstract
A new approach based on modified stress and strain with considering micromechanics and dislocation theory, has been extended to find the deformation mechanism during hot deformation of particulate metal matrix composite. The impact of main influential processing parameters, such as temperature, strain, and strain rate in addition to reinforcement characteristics, i.e., particle size, and volume fraction, were successfully taken into account in the calculation of deformation activation energy and stress exponent. Besides, the effect of particle fracture, and diffusion relaxation around particles, were participated in the presented formulation. To evaluate the applicability of the developed formulation, different aluminum matrix particulate composites with different particle sizes and volume fractions were subjected to investigation. Using the modified recovery stress for calculating the activation energy, results in reduction of the stress exponent to a meaningful range. It was shown that deformation mechanisms in metal matrix composite and unreinforced alloy are the same. It was also found that for the low value of stress, i.e., the low strain rate and high temperature, the stress relaxation, and for the high value stress, the particle fracture, disturb the load transfer mechanism and reduce the impact of reinforcement on activation energy.
NSTL
Elsevier