Pressure effects on metallic glasses

Spiral fracture in metallic glasses and its correlation with failure criterion

“…Usually, the least square fitting method can supply better accuracy. The fitted tension and compression strength from the MohrCoulomb criterion agree well with literature reports [3,14], especially with Bruck et al's [14] reports of uniaxial tensile strength r t s ¼ 1:93 AE 0:03 GPa, and a uniaxial compression strength of r c s ¼ 2:12 AE 0:05 GPa with the same kind of BMGs. However, they [14] suggested that BMGs follow the pressure independent Mises criterion.…”

“…2, the curve from D-P criterion prediction is close to that by the M-C criterion in most regime of the normal stress, which explains why both criteria can capture the deformation of metallic glasses in certain boundary-value problems [21][22][23][24]. The D-P and M-C values are very consistent with Lewandowiski's report [3] using superimposed method. We further note that parameters A and B in Eq.…”

“…The pressure sensitivity of failure in metallic glasses has been a topic of active research since the early experimental work of Davis and Kavesh [1] on ribbons, and more recent work by a number of authors [1][2][3][4][5][6][7]. This topic is tied to understanding the fundamental aspects of plastic deformation mechanisms which are still not fully understood [2,8].…”

“…For example, tension and compression tests conducted at one atmosphere by Donovan [10] found that the failure strength of Pd 40 Ni 40 P 20 followed the Mohr-Coulomb failure (M-C) criterion. Various works by Lewandowski et al [3][4][5][6][7] found only a moderate normal stress or pressure sensitivity for tests conducted with superimposed hydrostatic pressure when analyzed with either a M-C or Drucker-Prager (D-P) criterion, despite relatively large changes in fracture angle [3][4][5] going from tension to compression at atmospheric pressure. This asymmetry in fracture angle was later shown to be influenced by stress concentrations at the sample/platen interface that biased the compression fracture angles, later rectified by the design of tapered grips [11,12].…”

“…This topic is tied to understanding the fundamental aspects of plastic deformation mechanisms which are still not fully understood [2,8]. Experimentally, the pressure sensitivity of failure can be directly examined by conducting experiments with superimposed hydrostatic pressure [1,[3][4][5][6][7] in the manner of Bridgman [9], while any tension/compression asymmetry that exists at one atmosphere may also indicate some pressure sensitivity. For example, tension and compression tests conducted at one atmosphere by Donovan [10] found that the failure strength of Pd 40 Ni 40 P 20 followed the Mohr-Coulomb failure (M-C) criterion.…”