Effect of stirring time on viscoelastic properties of liquid gallium-oxide amalgams

This study investigated the effect of mechanical stirring time on liquid gallium (Ga)-oxide amalgams using linear and nonlinear viscoelastic properties in dynamic oscillatory shear. The liquid Ga-oxide amalgams with different stirring times were prepared by exposing liquid Ga to the atmosphere under continuous stirring. Linear viscoelasticity of all amalgams exhibited an elastic-dominant behavior. When plotted versus stirring time, elastic modulus increased gradually, which was described successfully by a power-law-type equation for a percolation behavior. The nonlinear viscoelasticity of the amalgams was analyzed using the conventional strain-sweep data and the sequence of physical processes (SPP) method. The critical strain amplitudes determined from the strain-sweep data showed that the yielding of the amalgams occurred earlier and more gradually with increasing stirring time. The SPP analysis using transient Cole–Cole plots revealed that all amalgams experienced intracycle nonlinear behavior consisting of three physical processes (recovery, elastic softening, and yielding) within an oscillation cycle. Intriguingly, the structure recovery rate evaluated by the maximum intracycle elasticity exhibited a nonmonotonic behavior, where the maximum recovery rate was achieved at the stirring time of 5 min. Finally, taking both linear and nonlinear properties, we suggested a material–property co-plot for the printability evaluation of liquid Ga-oxide amalgams.

Graphical Abstract