Processing map for hot working of 6061 Al–10 vol.-%Al<inf>2</inf>O<inf>3</inf> metal matrix composite

The processing map for hot working of 6061 Al–10 vol.-%Al2 O3(p) particulate reinforced cast and extruded composite material has been generated covering the temperature range 350–550°C and the strain rate range 0·001–100 s−l, based on the dynamic materials model. The efficiency of power dissipation η, given by (2m/m + 1), where m is the strain rate sensitivity, is plotted as a function of temperature and strain rate to obtain a processing map. A domain of dynamic recrystallisation has been identified, with a peak efficiency of 32% occurring at 550°C and 0·1 s−l. Another domain occurs at 350°C and 0·001 s−l, having a similar efficiency level, which is identified with interface cracking. The characteristics of these domains have been established with the help of microstructural evaluation and hot ductility measurements. Optimum hot working parameters are 550°C and 0·1 s−l, whereas microstructural instability occurs at strain rates higher than 10 s−l at all temperatures. © 1995 The Institute of Materials.