Hot deformation behavior of mechanically alloyed Al6063/0.75Al2O3/0.75Y2O3 nano-composite—A study using constitutive modeling and processing map

The hot deformation behavior of mechanically alloyed (MA’ed) Al6063/0.75Al2O3/0.75Y2O3 nano-composite was characterized in the temperature and strain rate ranges of 300–500 °C and 0.001–1 s−1 using compression test. Hot workability is interpreted by processing maps based on dynamic material modeling (DMM) and constitutive model was established based on sine-hyperbolic Arrhenius kinetic rate equation. Dynamic recrystallization (DRX) occurs in the temperature range of 400–500 °C and strain rate range of 0.001–0.1 s−1. The optimum processing parameters for hot working of MA’ed Al6063/0.75Al2O3/0.75Y2O3 nano-composite was identified to be in two domains, viz.: (i) T = 395–440 °C and ε ˙ = 0.001 – 0.01  s − 1 and (ii) T = 440–500 °C and ε ˙ = 0.003 – 0.01  s − 1 respectively with maximum efficiency of about 37–39% respectively. At strain rates ranging from 0.1 to 1 s−1 the nano-composite exhibits flow instability for all temperatures investigated. The average apparent activation energy for hot deformation is calculated to be 181 kJ/mol and flow behavior of the material was styled through a constitutive model. The reasons for the flow instability have been observed to be the surface cracking, void formation, matrix cracking, pores and wedge cracking.