Fabrication of Rod type Cu_(54)Ni_6Zr_(22)Ti_(18) Bulk Amorphous Alloy by Warm Extrusion Process

摘要

In this study, rod type Cu_(54)Ni_6Zr_(22)Ti_(18) bulk amorphous alloy fabricated by warm extrusion of amorphous powders was investigated. To get bulk type amorphous alloy, the Cu_(54)Ni_6Zr_(22)Ti_(18) amorphous powders which has a particle size below 63□ and wide supercooled liquid region of 53K were prepared by a high-pressure gas atomization method. The powders were filled in a Cu can with an inner dimension 20×2×50mm in air, evacuated, sealed and then pre-compacted in the press. Before extrusion, the billet was heated with heating rate of 50K/min and the holding time was about 5min. The extrusion temperature was 723K and the extrusion ratio was increased from 2 to 5. By warm extrusion of amorphous powders, a fully amorphous Cu_(54)Ni_6Zr_(22)Ti_(18) bulk type alloys were successfully synthesized. The conditions for extrusion were decided based on the time-temperature-transformation curve and DSC analysis. Phase analysis was performed by XRD. The result of the phase analysis indicated that Cu_(54)Ni_6Zr_(22)Ti_(18) bulk rod type samples having fully amorphous phase could be obtained until extrusion ratio of 4 at extrusion temperature of 723K, but partial crystalline phase would be observed in the bulk rod type alloy fabricated at extrusion ratio of 5.