Hot workability of PM 8009Al/Al2O3 particle-reinforced composite characterized using processing maps

High-temperature compression testing of powder metallurgy (PM) 8009AI alloy reinforced with 15 vol% Al2O3 particles was performed at temperatures of 400-550 degrees C and strain rates of 0.001-1 s(-1). Its constitutive behavior and processing maps were investigated, and the related microstructural evolutions were characterized by scanning and transmission electron microscopy. The results showed that the stress peak decreased with increasing deformation temperature and decreasing strain rate, which could be described by the Zener-Hollomon parameter Z of the hyperbolic sine relation. The processing map constructed at a strain of 0.5 exhibited two safe processing domains: 500-530 C at 0.001-0.003 s(-1) and 530-550 degrees C at 0.001-0.01 s(-1). After taking into account the processing map, efficiency of power dissipation and microstructural observations, the optimum processing domain corresponding to 530-550 degrees C/ 0.001-0.01 s(-1) was determined. As increasing deformation temperature and decreasing strain rate, the composite substructures with high density of dislocations were transformed into subgrains with distinct shapes and the fine dispersed Al-12(Fe,V)(3)Si phase coarsened inside the matrix, which exhibited typical dynamic recovery (DRV) characteristics. In addition, the interaction of the dislocation-dispersed phase Al2O3 particle and its effect on the hot deformation behavior of the 8009AI/Al2O3 composite were discussed. (C) 2018 Elsevier Ltd. All rights reserved.