Microstructure Characterization of Hot Extruded 7075 Al Bar with Different Passes and Temperatures
The influence of temperatures and passes on hot extruded 7075 Al bar were investigated using hydraulic press. The microstructures were observed using optical microscopy. The results showed that the as received AL bar consists of lamellar grain structures, and that equiaxed mixed grain size were observed with different passes at 320°C. Continuous dynamic recrystallization (CDRX) is responsible for the formation of small grain. The large grain tends to increases with more passes due to longer holding time. CDRX were observed for one pass only at 480°C. Lamellar grain structures were formed with different passes at 480°C.The lamellar grain structures are aligned at 50° to 70° to compression direction from one pass to four passes.
Y. B. Yang et al., "Microstructure Characterization of Hot Extruded 7075 Al Bar with Different Passes and Temperatures", Advanced Materials Research, Vols. 217-218, pp. 1679-1682, 2011