Estimate of the Maximum Strength of Metallic Glasses from Finite Deformation Theory

Maximum strength sets the limit of a material’s intrinsic resistance to permanent deformation. Its significance, however, lies not in the highest strength value that a solid can possibly achieve, but rather in how this quantity is degraded, from which one could decipher the underlying mechanisms of yielding in a real material. A wide range of maximum strength values have been measured experimentally for metallic glasses. However, the true maximum strength remains unknown to date. Here, using finite deformation theory, we give the first theoretical estimate of the ultimate strength of metallic glasses. Our theoretical results, along with those from experiment and simulation, lead us to several mechanisms of degradation of the theoretical strength that are closely connected to correlated atomic motion with varying characteristic length in real metallic glasses.

Figure 1

(a) The scaled shear stress vs strain. (b) The effective shear modulus vs shear strain.

Figure 2

(a) The scaled tensile and compressive stress vs strain. (b) The Young’s modulus $E_{100}$ vs uniaxial strain.

Figure 3

The relation between the “achievable maximum strength” and the (inverse) critical length of the correlated atomic motion at the onset of yielding. The dotted line is a guide for the eyes.