Microstructure evolution and flow behavior of hot-rolled aluminum – 5% B4C composite

Differential strain rate compression tests were conducted to study flow behavior of hot rolled Al–5 wt% B4C composite as a function of sample orientation (longitudinal and transverse) over the temperature and strain rate ranges of 25–500 °C and 10−4 to 1 s−1, respectively. The longitudinal samples are found to show lower flow stress than that shown by the transverse samples in the temperature range of 25–200 °C. The reverse becomes true at higher temperatures of 300–500 °C. The values of stress exponent (n) and activation energy for deformation (Q), based on applied stress, ranged from 10 to 46 and 307–416 kJ/mol, respectively. However, by considering effective stress, these values were reduced to n = 8 and Q = 126–190 kJ/mol. This stress exponent ofn = 8 is further reduced to n = 5 by considering substructural evolution, which suggests the dislocation climb creep mechanism to be favorable for deformation.