In situ TEM observation of phase transformation in bulk metallic glass composites

Abstract

Transformation-induced plasticity is a fundamental solution for improving the ductility of bulk metallic glass composites (BMGCs). However, the underlying mechanism remains controversial. Here, by using in situ transmission electron microscopy, we present direct observation of the transformation dynamics from β/ω phase to α' phase of the crystalline dendrites in a TiZrCuBe BMGC under uniaxial tensile deformation. The transformation redistributes the stress in the adjacent matrix, making interfacial regions potential preferential sites for shear band nucleation. The high density of nucleation sites is believed to promote the formation of shear band networks and enhance the ductility of BMGCs. IMPACT STATEMENTDirectly evidencing that phase transformation of the crystalline precipitates occurs first and triggers shear banding in the glassy matrix during the deformation of BMGCs.

In Situ TEM Characterization and Modulation for Phase Engineering of Nanomaterials

“…The authors studied the transformation dynamics from the β/ω-phase to the α′-phase in a TiZrCuBe metallic glass composite. The phase transformation produces preferential sites for shear banding nucleation during deformation . Similarly, in another experiment, the superelasticity of VO 2 nanowires induced by phase transformation was studied using a PI 95 PicoIndenter system coupled with a Hysitron PTP device (Figure d).…”

“…The phase transformation produces preferential sites for shear banding nucleation during deformation. 292 Similarly, in another experiment, the superelasticity of VO 2 nanowires induced by phase transformation was studied using a PI 95 PicoIndenter system coupled with a Hysitron PTP device (Figure 18d). The in situ TEM observations demonstrate that the pre-existing M2 phase can act as an initiation site during the M2 phase motion and promote the M1−M2 phase transition.…”

Defect-characterized phase transition kinetics

“…Promising studies have already emerged. 209,[348][349][350][351][352][353][354][355][356][357] In addition to direct observations, more quantitative analyses of the evolution of the structural and chemical information during phase transitions, and how they can be altered by the presence of defects are of particular interest, but might be very difficult tasks to accomplish. Active developments are still ongoing in order to push the current limits of experimental techniques.…”