Micro-to-nano-scale deformation mechanism of a Ti-based dendritic-ultrafine eutectic alloy exhibiting large tensile ductility

Year: 
2016
Month: 
11
Day: 
24
Pages: 
673-678
DOI: 
10.1016/j.msea.2016.11.082
Author(s): 
Type: 
Journal Articles
Journal: 
Materials Science & Engineering A
Volume: 
682
Abstract: 

Deformation mechanism of a new Ti-16.6Nb-6Co-5.1Cu-6.5Al (at.%) alloy is studied using scanning and transmission electron microscopy. The alloy consists of micrometer-sized β-Ti dendrites and an ultrafine-eutectic composed of β-Ti and TiCo phases. The yield strength of the alloy (1.1 GPa) is comparable to that of the metallic glass composites and is coupled with large tensile ductility of about 11%. Transmission electron microscopy analysis reveals that slip lines formed during deformation in the dendrites penetrates the eutectic resulting in formation of a stepped interface and an extra area serving to accommodate shear strains. The β-Ti eutectic component can deform plastically to a high degree supporting deformation of TiCo. The results suggest that microstructural design of the eutectic is important for controlling tensile ductility of dendritic-ultrafine eutectic alloys.