Mechanical performance and fracture behavior of Fe₄₁Co₇Cr₁₅Mo₁₄Y₂C₁₅B₆ bulk metallic glass

Abstract

The mechanical properties of a new Fe 41 Co 7 Cr 15 Mo 14 Y 2 C 15 B 6 bulk glassy alloy were studied by impact bending, compression, and hardness tests carried out at room temperature. The compressive fracture strength, elastic strain to fracture, Young's modulus and Vickers hardness were measured to be 3.5 GPa, 1.5%, 265 GPa, and 1253 kg mm −2 , respectively. The fracture mode of the glassy alloy under uniaxial compression is different from those of other bulk metallic glasses in that this fracture mode causes the samples to be broken, in an exploding manner, into a large number of micrometer-scale pieces. The fracture mechanisms of this bulk glassy alloy under bending and uniaxial compression are discussed based on the observation of the fracture surfaces. Vickers indentation tests indicate that the structure of the glassy ingot may be inhomogeneous.

Instability of crack propagation in brittle bulk metallic glass

“…Recently, several families of brittle bulk metallic glasses (BMG), such as Mg-based [19,20], Fe-based [21,22] and rare-earth-based BMG [23], have been developed. Compared with previous tough BMG with notch fracture toughness (K c ) value >20 MPa m 1/2 [24], , which are very close to those of oxide glasses [24].…”

“…Recently, a competition process between the local plastic softening mechanism and the local cleavage mechanism has been proposed to elucidate the energy dissipation in BMG fracturing [30]. As the fracture behavior is a dynamic process, its fractographies will evolve as the crack propagates due to the changes in loading strain-rate [30], crack propagation speed [22] and the dynamic effects [27]. These factors will seriously affect the energy dissipation mechanism.…”

Size Effect on Shear Fracture and Fragmentation of a Fe57.6Co14.4B19.2Si4.8Nb4 Bulk Metallic Glass

“…[8,9] However, brittle BMGs always fail in split and fragmentation modes, exhibiting mirror and hackle regions on the fracture surface. [6,[10][11][12][13] Recently, nano-scale features were observed in the mirror region on the fracture surface of brittle BMGs. [10,12,[14][15][16][17][18][19][20] It was argued that these features correspond to nano-scale plasticity, and the fracture toughness was calculated according to these nano-scale feature.…”

“…It was found that the Sample S1 failed by a fragmentation mode with a bombing sound, producing a lot of fine fragments, [6,11] as shown in Figure 2(a). Mirror and hackle regions were formed on the fracture surface (see Fig.…”

Numerical study of pile-up in bulk metallic glass during spherical indentation

“…Once the shear bands are formed, BMGs fail catastrophically within the main shear band and show little plasticity [9][10][11] , thus limiting the application of BMGs as engineering material. So, for the sake of perceiving the plastic instability behavior and applications in engineering, much effort has been devoted to the mechanism of formation and evolution of shear bands in BMGs [12][13][14][15][16][17][18] …”