Effect of hot rolling temperature and thermal cycling on creep and damage behavior of powder metallurgy processed Al–SiC particulate composite

Tensile creep behavior of Al–5SiCp composite, powder metallurgy processed and hot-rolled at either 400 °C (400-HRC) or 600 °C (600-HRC), has been examined. Creep-tests have been carried out at temperature and stress ranges of 325–400 °C and 9–21 MPa, respectively. The creep behavior has been examined by analyzing steady-state creep rate, time to rupture, Larson–Miller parameter (LMP), strain fractions in primary, secondary and tertiary stages, with assessment of damage and dimple size. The creep resistance of 400-HRC with higher dislocation density is found as greater than that of 600-HRC, whereas apparent stress exponents and activation energies exceed that for dislocation climb. The results suggest possibility of life prediction using Monkman–Grant relationship and LMP variation with stress. Thermal cycling between 500 °C and 0 °C is more effective in improving creep resistance at lower temperatures, and is more beneficial for 400-HRC than for 600-HRC, confirming positive role of strain-hardening.