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

Abstract Differential strain rate compression tests were conducted to study flow behavior of hot rolled Al–5 wt% B 4 C 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 of n  = 8 is further reduced to n  = 5 by considering substructural evolution, which suggests the dislocation climb creep mechanism to be favorable for deformation.