Solid Solubility of Si in Al under High Pressure

By making use of a 15 mm cubic anvil apparatus, Al–Si alloys of Si-concentration up to 15 at% were studied at a pressure of 54 kbar. The liquidus, solidus and solvus of the Al-rich alloys were determined by means of the 4-probe electric resistance measurement. The solubility limit of Si in Al was extended beyond 15 at% at 54 kbar in comparison with 1.59 at% at 0 kbar. The resistivity of the alloy was increased by a solution of Si with a gradient of 0.5 µΩcm/at% up to 15 at%Si. The alloy quenched under high pressure was examined by X-ray diffractometry showing that Si was completely solid-dissolved in Al. The quenched alloy was much more hardened than the ordinary two-phase alloy at 0 kbar.