Recent Progress of Zr-Based Bulk Amorphous Alloys

摘要

This paper reviews the recent progress of bulk amorphous Zr-based alloys. The bulk amorphous alloys consist of the multicomponent alloy systems which satisfy the three empirical rules for the achievement of large glass-forming ability. The scientific significance of the three empirical rules have also been investigated based on a number of experimental data. By choosing appropriate multicomponent alloy compositions which satisfy the three empirical rales, bulk amorphous alloys with diameters up to 50 mm have been produced in a cylindrical form by various solidification processes. The bulk amorphous alloys exhibit good characteristics of high tensile strength, good ductility, low coefficient of thermal expansion. elinvar characteristics and high corrosion resistance. Furthermore, the bulk amorphous alloys heated in the supercooled liquid state can be easily deformed into various kinds of shapes through viscous flow. The ideal Newtonian flow has been identified to be achieved in the supercooled liquid. Besides, the utilization of the ideal superplasticity enabled the production of a bulk amorphous alloy with nearly full density by extrusion of atomized amorphous powders. The extruded bulk amorphous alloys also exhibit the same high tensile strength as that for the cast bulk and melt-spun ribbon amorphous alloys. It is therefore expected that the bulk amorphous Zr-based alloys with diameters up to about 50 mm. which can be produced through the two methods of conventional casting and warm extrusion, develop as a new type of engineering materials because of the simultaneous achievement of the above-described useful characteristics.