Published online by Cambridge University Press: 31 January 2011
Tension and stress-relaxation behaviors of a La62Al14Cu11.7Ag2.3Ni5Co5 bulk metallic glass (BMG) as a function of isothermal annealing time have been investigated. It is found that annealing at 373 K below the glass-transition temperature (423 K) of the BMG alloy causes an increase of special heat difference at the glass transition and density of the alloy, indicating a reduction of free volume in the BMG alloy with annealing time. Compared with the as-cast sample, the fracture strength, Vickers hardness, viscosity, Young’s modulus, and stress-relaxation stability of the annealed BMGs increase with annealing time, which is caused by the reduction of free volume in the annealed samples. Furthermore, a change of fracture morphology from a mixture of smooth and furrow zones in the as-cast sample to a mainly furrow zone in the sample annealed for 8 h was also observed. All samples exhibit brittle behavior during tension tests.