High strain rate superplasticity of supercooled liquid for amorphous alloys

The recent discoveries of a number of new amorphous alloys with a wide supercooled liquid region before crystallization have enabled the progresses of basic science and engineering utilization of the supercooled liquid. The supercooled liquid has a high strain rate sensitivity (m-value) of 1.0, implying the achievement of an ideal superplasticity. Furthermore, the high m-value was found to cause extremely large tensile elongations of about 1.5 × 10⁵ % at ordinary strain rates of 10^-2 to 10^-1 s^-1 and large compressive elongations reaching nearly 100 % at the ultrahigh strain rate of 10⁶ s^-1. The appearance of the extremely large elongations and the ultrahigh strain rate superplasticity which have not been obtained for crystalline superplastic alloys is promising for future development of the supercooled liquid to produce superplastic materials with various shapes.