Flow and fracture of a Ni-Fe metallic glass

Fatigue and fracture behavior of bulk metallic glass

“…The fracture surface is basically perpendicular to the loading direction rather than inclined to it. Fatigue cracks originate from the surface, Alpas et al [48] Ni 78 Si 10 B 12 55 deg Bengus et al [49] Fe 70 Ni 10 B 20 60 deg Davis and Yeow [50] Ni 49 Fe 29 P 14 B 6 Si 2 53 deg He et al [38] Zr 52.5 Ni 14.6 Al 10 Cu 17.9 Ti 5 55 to 65 deg Inoue et al [51] Zr 65 Ni 10 Al 7.5 Cu 7.5 Pd 10 50 deg Inoue et al [42] Cu 60 Zr 30 Ti 10 54 deg Liu et al [37] Zr 52.5 Ni 14.6 Al 10 Cu 17.9 Ti 5 53 to 60 deg Lewandowski and Lowhaphandu [25] Zr 40 [43] Zr 62 Ti 10 Ni 10 Cu 14.5 Be 3.5 57 Ϯ 3.7 deg Megusar et al [52] Pd 80 Si 20 50 deg Mukai et al [53] Pd 40 Ni 40 P 20 56 deg Noskova et al [54] Co 70 Si 15 B 10 Fe 5 60 deg Takayama [55] Pd 77.5 Cu 6 Si 16.5 50 to 51 deg Xiao et al [47] Zr 52.5 Cu 15 Al 10 Ni 10 Be 12.5 55 deg Zhang et al [39] Zr 59 Cu 20 [28,29,30] On the surface, there are several cracks (Figure 6(b)). Besides (Figure 6(a)), there is a halfcircle region, which corresponds to the initiation of the surface fatigue crack.…”

“…First, the fracture strength under compression is slightly higher than that under tension for most metallic glasses, as listed in Table I. Second, as shown in Tables II and III, [2,25,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] the tensile shear fracture angle T is larger than 45 deg, but the compressive shear fracture angle C is smaller than 45 deg, i.e., [1] Third, the fracture surface features are also different under the two loading modes, as shown in Figures 4 and 5. For better understanding of such asymmetry in metallic glasses, the Mohr-Coulomb criterion was employed both for compressive and tensile fracture.…”

Unified Tensile Fracture Criterion

“…We have previously proposed that the radiating veinlike patterns give evidence for a promotion effect of the normal stress on the tensile shear fracture [12 -14]. Besides, many other investigators also observed an obvious deviation of the tensile shear fracture angle from 45 ; Table I lists the T values of various BMGs reported so far [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], covering several different alloy systems, such as Zr-, Cu-, Fe-, Co-, La-, Al-, Ni-, Pd-based alloys, etc. The findings outlined above strongly indicate that the deviation of the tensile shear fracture plane from 45 is a common phenomenon in BMGs.…”

“…During the last ten years, a new class of material, i.e., bulk metallic glass (BMG), was discovered and attracted worldwide attention due to its unique properties [6,7]. Their plastic deformation and fracture are always localized in some shear bands with little overall plasticity [8][9][10][11]. However, up to now it is not clear for this type of material which is the preferential shear plane (or yield plane) under different loading modes.…”

Propagation and Deflection of Shear Bands in Metallic Glass under Circumferential Constraint

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For monolithic bulk metallic glasses, deformation and fracture are always associated with the initiation and propagation of localized shear bands, finally leading to failure in a shear mode. [1,2] Thus, it is of considerable scientific interest to investigate the formation and propagation of shear bands in metallic glass experimentally and theoretically. [3][4][5][6][7] Generally, due to the long-range disorder and macroscopically isotropic nature of amorphous alloys, [8] shear bands often initiate along some shear plane, which is convenient to investigate the yielding or fracture criterion based on the observations of the angles between shear bands and stress axis.

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