Progress in Consolidation of Amorphous Zr-based Powder into Bulk Metallic Glass

摘要

Equal channel angular extrusion (ECAE) is used to consolidate amorphous Vitreloy 106a (Zr_(58.5)Nb_(2.8)Cu_(15.6)Ni_(12.8)Al_(10.3)) powder into bulk metallic glass. Consolidations are performed on gas atomized powder containing 1280 ppmw oxygen encapsulated in copper cans and 780 ppmw oxygen powder encapsulated in nickel cans in a 90? die-angle tool at temperatures above the glass transition temperature (T_g) but below the rapid crystallization temperature (T_x), in the supercooled liquid region (AT). Results show that V106a is successfully consolidated to nominal full density after one extrusion pass. Good particle-to-particle bonding and significant particle deformation are observed in the consolidated alloy. A lower oxygen content is beneficial due to the larger undercooled region and the additional time for processing. The low oxygen content material shows little change in thermal stability after being consolidated when compared to the original powder but fine interparticle cracks are observed in some of the consolidates. ECAE appears to be a viable method for consolidating amorphous metal powders into bulk amorphous metal.