PROCESSING MAP FOR HOT-WORKING OF 6061-AL-10 VOL-PERCENT-AL2O3 METAL-MATRIX COMPOSITE

The processing map or hot work ing of 6061 Al-10 vol.-%Al2O3(p) partic ulate reinforced cast and extruded composite material has been generat ed covering the temperature range 350-550 degrees C and the strain rat e range 0.001-100 s(-1), based on the dynamic materials model. The eff iciency of power dissipation eta, given by (2m/m + 1), where m is the strain rate sensitivity, is plotted as a function of temperature and s train rate to obtain a processing map. A domain of dynamic recrystalli sation has been identified, with a peak efficiency of 32% occurring at 550 degrees C and 0.1 s(-1). Another domain occurs at 350 degrees C a nd 0.001 s(-1), having a similar efficiency level, which is identified with interface cracking. The characteristics of these domains have be en established with the help of microstructural ecaluation and hot duc tility measurements. Optimum hot working parameters are 550 degrees C and 0.1 s(-1), whereas microstructural instability occurs at strain ra tes higher than 10 s(-1) at all temperatures.