HOT DEFORMATION BEHAVIOR AND MICROSTRUCTURAL EVOLUTION OF HOMOGENIZED 7150 ALUMINUM ALLOYS MICRO-ALLOYED WITH ZR AND V

Hot deformation behavior of homogenized 7150 aluminum alloys micro-alloyed with 0.12% Zr and 0.11% V was studied by compression tests conducted at various temperatures and strain rates. The microstructural evolution was investigated using an optical microscope and the electron backscattered diffraction technique. The results showed that the peak flow stress of alloy 7150 increased due to the addition of Zr or V. The hot deformation activation energy of the base alloy was determined to be 209.0 kJ/mol, which increased to 244.7 kJ/mol and 248.7 kJ/mol when alloyed with 0.12% Zr and 0.11% V respectively. The softening mechanism of the base alloy was dynamic recovery during hot deformation at low temperatures (300 degrees C - 400 degrees C), which transformed to dynamic recrystallization at a high temperature (450 degrees C) and a low strain rate (0.001 s(-1)). Adding Zr or V generally displayed a retardation of the dynamic recovery and inhibition of the dynamic recrystallization, and hence resulted in the increase of flow stresses.