Effects of consolidation temperature and pressure on microstructures and mechanical properties of Cu-based bulk amorphous alloys consolidated by spark plasma sintering

This study aims at fabricating Cu-based bulk amorphous alloys by a spark plasma sintering (SPS) method. Consolidation temperature, consolidation pressure, and holding time were established to obtain good microstructures and compressive properties of consolidated amorphous alloys. Bulk amorphous alloys having a few micropores and nanocrystalline phases could be obtained with a consolidation pressure of 80 MPa, but were fractured in an intergranular mode along prior powder boundaries. Microstructures and compressive properties of the alloys consolidated with a pressure of 300 MPa were significantly modified as prior amorphous powders were sufficiently bonded without micropores. Fractographic investigation of these alloys indicated that vein patterns appeared on fracture surfaces as amorphous powders were strongly bonded during the high-pressure consolidation. These findings suggested that the high-pressure consolidation was effective in suppressing the crystallization of amorphous phases and in strongly bonding amorphous powders.