Production of Si55 Al20 Fe10 Ni5 Cr5 Zr5 bulk amorphous alloy by hot pressing

Abstract

The temperature dependence of the relative density was examined for a Si₅₅ Al₂₀ Fe₁₀ Ni₅ Cr₅ Zr₅ alloy which was produced by hot pressing of the amorphous powder during heating up to various temperatures under a critical pressure of 1·5 GPa through a heating/pressing cycle. The density of the compacts increased with increasing temperature and reached a maximum near the crystallisation temperature of 698 K. The relative density of the compacts reached 98·3% at the critical condition of 1·5 GPa and 687 K. The hardness value of the bulk specimen was 940 HV(10 gf, 0·098 N), corresponding to that of the amorphous ribbon. Exposure to higher temperatures resulted in the precipitation of the crystalline phase. The present results indicate that Si based alloys can be produced in a compact form with a low fraction of voids by hot pressing the amorphous powder.