Elastostatic reversibility in thermally formed bulk metallic glasses: nanobeam diffraction fluctuation electron...

Area of Science:

• Materials Science
• Materials Engineering
• Condensed Matter Physics

Background:

• Bulk metallic glasses (BMGs) offer exceptional shaping capabilities for micro- and nanodevices.
• Thermoplastic forming (TPF) of BMGs can degrade their intrinsic mechanical and thermal properties, especially under complex stress states.

Purpose of the Study:

• To investigate the effects of elastostatic loading (ESL) on BMGs previously subjected to TPF.
• To determine if ESL can restore and enhance the properties of BMGs, and understand the underlying mechanisms.

Main Methods:

• Thermoplastic forming (TPF) and elastostatic loading (ESL) were applied to BMG samples.
• Differential scanning calorimetry (DSC) was used to analyze thermal properties.
• High-resolution transmission electron microscopy (HRTEM) and fluctuation electron microscopy (FEM) were employed to study structural changes.

Main Results:

• ESL fully reversed the deterioration of room-temperature plasticity caused by TPF.
• ESL induced a rejuvenation mechanism, increasing resistance to strain softening.
• Temporary reductions in the supercooled liquid region and crystallization enthalpy were fully reversible.
• ESL treatment led to modifications in medium-range structural order, restoring mechanical and thermal properties.

Conclusions:

• ESL is a viable post-processing treatment for TPF-processed BMGs, restoring and enhancing their properties.
• The combination of TPF and ESL opens possibilities for advanced BMGs in micro- and nanomechanical devices.
• Restored mechanical and thermal performance is linked to modifications in the medium-range structural order of BMGs.