Formation of nanocrystals in Ti78Fe15Si7 amorphous alloy with a wide supercooled liquid region

An as-quenched amorphous Ti78Fe15Si7 alloy with a large supercooled liquid region (61 K) was investigated using X-ray diffraction, differential scanning and transmission electron microscopy (TEM). This amorphous alloy transforms into primary nano-sized beta-Ti phase particles (<20 nm) of spherical shape upon a first exothermic reaction. The remaining amorphous phase transforms to the Ti2Fe phase followed by the Ti5Si3 phase upon the second and third exothermic reaction. The tensile fracture strength was 1318 MPa for the amorphous alloy and increased up to 1876 MPa for a volume fraction of 15% primary beta-Ti phase. (C) 2003 Elsevier B.V. All rights reserved.