Effects of Pressure and Temperature on Consolidation of Nanocrystalline MA Powder of Al-10.7 at%Ti-0.6 at%Fe Supersaturated Solid Solution

Abstract

The powder of a single phase of the Al-10.7 at%Ti-0.6 at%Fe supersaturated solid solution with an average crystallite size of 11 nm has been obtained from a pure Al and Ti mixed powder by means of a high energy planetary ball mill. The mechanically alloyed (MA) powder was consolidated into cylinders 4 mm in diameter and 2.5 mm in height at temperatures of 473773 K under hydrostatic pressures of 0.1 MPa3 GPa. The consolidation at high temperatures causes the decomposition of the supersaturated solid solution obtained by MA, whereas the compacts consolidated at low temperatures retain the supersaturated solid solution and nanostructure. The upper limiting temperature where the compact can retain the supersaturated solid solution becomes higher with increasing consolidation pressure, and the application of high pressure consequently permits consolidating the MA powder at higher temperature without decomposing the supersaturated solid solution. On the other hand, the higher consolidation pressure and temperature can give higher density and hardness to the compact. Thus the application of high pressure is effective for the consolidation of MA powder with the retention of the supersaturation and nanostructure.