Upset Deformation of Amorphous Mg<SUB>85</SUB>Y<SUB>10</SUB>Cu<SUB>5</SUB> Alloy in an Extended Supercooled Liquid Region Effectuated by Rapid Heating

Abstract

We have developed a new thermomechanical equipment in which the sequential processes consisting of rapid heating at a rate of 300 K/s, upset deformation at a speed of 50 mm/s and immediate water cooling can be performed through a computer program. This equipment is expected to enable the deformation of an amorphous alloy into various shapes by utilizing the viscous flow resulting from the extension of the supercooled liquid region caused by the rapid heating. By using the equipment, the changes in Tg and Tx by rapid heating were also examined for an amorphous Mg85Y10Cu5 alloy in the cylindrical shape of 5mmφ×10mm. The increase in heating rate from 0.67 to 230 K/s caused the increase in Tg from 435 to 456 K and Tx from 463 to 518 K and the temperature interval between Tg and Tx, ΔTx, also increases from 28 to 62 K. In the extended supercooled liquid region, the upset deformation to 50% reduction ratio in height was carried out within a short time of 0.5 s. The extension of the supercooled liquid region by using the equipment as well as the easy deformation in the extended supercooled liquid region is important in the subsequent development of amorphous alloys.