Dendrite size and tensile ductility in Ti-based amorphous alloys containing ductile dendrites

Three Ti-based amorphous alloy sheets containing ductile dendrites were fabricated by varying cooling rate, and deformation mechanisms related with improvement of tensile ductility were investigated by observing initiation and propagation processes of deformation bands at dendrites. The alloy sheets contained many dendrites (volume fraction; 64 similar to 68%, size: 2.1-9.4 mu m), and showed the yield strength of 1.5 GPa and the elongation up to 5%. According to the observation of tensile deformation behavior of the 3-mm-thick alloy sheet, many deformation bands were formed inside dendrites in several directions, and deformation bands met crossly each other to form widely deformed areas. Since the wide and homogeneous deformation in this alloy sheet beneficially worked for the tensile strength and ductility simultaneously, the optimum size of dendrites and thickness of the alloy sheets were about 3.1 mu m and 3 mm, respectively. (C) 2013 Elsevier B.V. All rights reserved.