Degree of local structural ordering and its correlation with the glass forming ability of alloys

The degree of local structural order in amorphous solids and liquids has been investigated in CuHf alloys for the first time. X-ray diffraction experiments and thermal analysis show that the local structural order is strongly composition-dependent. For the CuHf alloys, it has been found that a close relationship exists between the degree of local ordering and the glass forming ability. Comparisons between the present alloys and those studied previously show that local structural order in glass formation is determined by the dominant vitrification conditions (diffusion-controlled or nucleation-controlled). The local ordering structures act as random fields against crystallization when the primary crystallization mechanism for the undercooled melts is the formation of intermetallic crystals.