UPSET DEFORMATION OF AMORPHOUS MG85Y10CU5 ALLOY IN AN EXTENDED SUPERCOOLED LIQUID REGION EFFECTUATED BY RAPID HEATING

We have developed a new thermomechanical equipment in which the sequen tial 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 en able the deformation of an amorphous alloy into various shapes by util izing the viscous flow resulting from the extension of the supercooled liquid region caused by the rapid heating. By using the equipment, th e changes in T(g) and T(x) by rapid heating were also examined for an amorphous Mg85Y10Cu5 alloy in the cylindrical shape of 5 mm(phi) x 10 mm. The increase in heating rate from 0.67 to 230 K/s caused the incre ase in T(g) from 435 to 456 K and T(x) from 463 to 518 K and the tempe rature interval between T(g) and T(x), DELTAT(x), also increases from 28 to 62 K. In the extended supercooled liquid region, the upset defor mation 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 usin g the equipment as well as the easy deformation in the extended superc ooled liquid region is important in the subsequent development of amor phous alloys.