Universal Additive Effect of Temperature on the Rheology of Amorphous Solids

Abstract

Extensive measurements of macroscopic stress in a 2D Lennard-Jones glass, over a broad range of temperatures (T) and strain rates (γ), demonstrate a very significant decrease of the flowing stress with T, even much below the glass transition. A detailed analysis of the interplay between loading, thermal activation, and mechanical noise leads us to propose that over a broad (γ, T) region, the effect of temperature amounts to a mere lowering of the strains at which plastic events occur, while the athermal avalanche dynamics remains essentially unperturbed. Up to the vicinity of the glass transition, temperature is then shown to correct the athermal stress by a (negative) additive contribution which presents a universal form, thus bringing support to and extending an expression proposed by Johnson and Samwer [Phys. Rev. Lett. 95, 195501 (2005)].

Statistical physics of elastoplastic steady states in amorphous solids: Finite temperatures and strain rates

“…To this purpose we will explore here the effect of temperature and of strain rates, separately and together, to assess whether indeed the existence of finite temperatures and strain rates obliterate the relevance of the rich plethora of findings at the AQS conditions. Our conclusion is that this is far from being true [14,15]. In fact, even when temperature or strain rates are enough to make the stress and energy fluctuations 'normal' (in a sense made precise below) the role of mechanical instabilities is still crucial.…”

“…To see the effect of temperature explicitly one introduces the probability to undergo a thermally activated plastic event at the strain value γ, denoted as P a (γ, T ) [14]. This probability was measured for a range of temperatures and is displayed in Fig.…”

Reversibility and hysteresis of the sharp yielding transition of a colloidal glass under oscillatory shear

“…The idea is that the applied shear provides an external field, to which microscopic rearrangements can couple; coupling also occurs between the rearrangements themselves, mediated by their elastic interactions, leading to long-range correlations in the microscopic deformation of slowly deformed glasses [13][14][15][16][17][18][19][20][21][22]. Colloidal glasses have played an important role in directly visualizing these microscopic correlations.…”

Cryogenic-temperature-induced transition from shear to dilatational failure in metallic glasses

“…Mechanical failure of metallic glasses continues to fascinate researchers [1][2][3][4][5], since dislocations, grain boundaries, crystallographic planes, etc., are not defined in this class of non-crystalline materials [6][7][8][9]. Instead, the shear transformation zone (STZ), i.e.…”