MECHANICAL-PROPERTIES OF ZR57TI5AL10CU20NI8 AMORPHOUS AND PARTIALLY NANOCRYSTALLIZED ALLOYS

2r(57)Cu(20)Al(20)Ni(8)Ti(5) amorphous cylinders of 8 mm diameters wer e cast with copper moulds. The mechanical properties of the amorphous alloys obtained were measured by compression tests. The as-cast amorph ous alloys show a high yield stress of about 1560 MPa and fracture str ess of 1650 MPa. Structural relaxation, through annealing below the gl ass transition temperature, for example, at 573 K for 40 min? increase s these values to about 1700 and 1760 MPa, respectively. Annealing of the amorphous alloy in the supercooled liquid region causes initial cr ystallization! but the residual amorphous phase becomes relatively sta ble. The partially crystallized amorphous alloy, for example with abou t 40% (vol) crystalline phase? still shows excellent strength, with a yield stress of 1700 MPa and a fracture stress of 1850 MPa. Both the a s-cast and annealed amorphous alloys show ductile deformation with ser rated flow before final fracture. These results indicate that amorphou s alloys with such crystallization behaviour can be quite safely hot-w orked near the glass transition temperatures. (C) 1997 Elsevier Scienc e S.A.