Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

Abstract

The impact of severe plastic deformation by high-pressure torsion on the relaxation of the glassy and supercooled liquid states of Pd 40 Ni 40 P 20 was investigated using a combination of differential scanning calorimetry, low-temperature heat capacity and fluctuation electron microscopy. The changes in the calorimetric signals due to deformation and subsequent heat treatments were analyzed and a correlation between deformation (rejuvenation) and annealing (relaxation) was found in relation to medium-range order (MRO). Moreover, a coupling between the occurrence of an exothermic peak in the supercooled liquid state and specific changes in the MRO types were identified. These findings are comprehended in a potential energy landscape scheme offering a new approach for MRO engineering of glasses.

X-ray photon correlation spectroscopy revealing the change of relaxation dynamics of a severely deformed Pd-based bulk metallic glass

“…Within the framework of the model proposed by Stratton and Voyles[43], the information on MRO clusters can be obtained by analyzing the change of the peak maximum of V as a function of 1/R 2 . Fig.6shows that there are two MRO correlation lengths present for the annealed (undeformed) sample which is in line with VR-FEM results obtained on PdNiP MGs[70,71]. Subjected to a deformation by 10 revolutions of HPT, the plateau at the larger MRO size originally observed for the annealed state disappeared.…”