Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Abstract

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pure elements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloy powder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overall powder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Si alloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification was clearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformation of particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis of the sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remained the alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at 59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to 702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strength of the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi, Al13Cr4Si4 and Al8Cr5 phases sintering process, resulting from the improvement of mechanical properties. We have obtained a fine and high purity Al–25Cr–5Si (at%) alloy powder, which has been successfully manufactured by gas atomization. The atomized Al–Cr–Si alloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Alloy powders have been densified using a pulsed current-activated sintering (PCAS) process. The Vickers hardness of the compacts by mixed powder was observed at 59.70 Hv and the compact using gas atomized powders on the temperature 1000 ℃ of the Vickers hardness increased to 702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strength of the compact with gas atomized powder increased to 802.07 MPa.