Preliminary assessment of flow, notch toughness, and high temperature behavior of Cu60Zr20Hf10Ti10 bulk metallic glass

Wesseling, P.; Nieh, T.G.; W.H., Wang,; Lewandowski, John J.

doi:10.1016/j.scriptamat.2004.03.034

Cited by 72 publications

(40 citation statements)

References 27 publications

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“…Due to inherent critical-castingthickness limitations, notch toughness measurements using cylindrical specimens with no pre-existing cracks are often reported for amorphous metals. 21,22 More specifically, the notch toughness measurements performed recently for Febased glasses by Lewandowski and co-workers 6,23 using specimens with configurations and dimensions similar to the present work are suitable for direct comparison.…”

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confidence: 70%

Glassy steel optimized for glass-forming ability and toughness

Demetriou¹,

Kaltenboeck²,

Suh³

et al. 2009

Applied Physics Letters

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An alloy development strategy coupled with toughness assessments and ultrasonic measurements is implemented to design a series of iron-based glass-forming alloys that demonstrate improved glass-forming ability and toughness. The combination of good glass-forming ability and high toughness demonstrated by the present alloys is uncommon in Fe-based systems, and is attributed to the ability of these compositions to form stable glass configurations associated with low activation barriers for shear flow, which tend to promote plastic flow and give rise to a toughness higher than other known Fe-based bulk-glass-forming systems. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3184792͔The remarkably high strength, modulus, and hardness of iron-based glasses, combined with their low cost, prompted an effort over the past five years to design amorphous steel suitable for structural applications. The development effort yielded glasses with critical rod diameters as large as 12 mm 1,2 and strengths in excess of 4 GPa. 3 These low-cost ultrastrong materials however exhibit fracture toughness values as low as 3 MPa m 1/2 , 4 well below acceptable toughness limits for structural materials. The low toughness has been linked to their elastic constants, specifically their high shear modulus, 5 which for some compositions exceeds 80 GPa. 3 Recent efforts to toughen these alloys by altering their composition yielded glasses with lower shear moduli ͑below 70 GPa͒, which exhibit improved notch toughness ͑as high as 50 MPa m 1/2 ͒ but compromised glass-forming ability ͑criti-cal rod diameters less than 3 mm͒. 5,6 In this study, we implement an alloy development strategy coupled with toughness assessment and ultrasonic measurements to design glassy steel alloys with particularly low shear moduli ͑below 60 GPa͒ that demonstrate high toughness ͑notch toughness in excess of 50 MPa m 1/2 ͒ yet adequate glass-forming ability ͑critical rod diameters as large as 6 mm͒.The link between the high shear modulus and the low toughness of Fe-based glasses rests on the argument that a high shear modulus implies a high resistance to relax stress by shear flow. In turn, this promotes cavitation and early fracture and thus limits toughness. Using a Frenkel-like analysis to study cooperative shearing, Johnson and Samwer 7 arrived at a quantitative expression for the activation energy for shear flow, that is, the energy barrier to initiate plastic flow. Specifically, a relationship was proposed between the shear-flow barrier W and the shear modulus G for a frozen-in atomic configuration at the glass transition temperature T g , given by W͑T g ͒ ϰ G͑T g ͒v m ͑T g ͒, 7 where v m is the molar volume, which usually varies little within an alloy family. Aside from their high G, the brittle behavior of these glasses can also be predicted by their high T g , which for some compositions exceeds 600°C. 1,2 The glass transition temperature is also a measure of W͑T g ͒, since the requirement for the liquid viscosity at T g ͑10 12 Pa s͒ gives W͑T g ͒Ϸ37RT g ....

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mentioning

confidence: 70%

Glassy steel optimized for glass-forming ability and toughness

Demetriou¹,

Kaltenboeck²,

Suh³

et al. 2009

Applied Physics Letters

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“…[2][3][4][5][6][7][8] This has renewed interest in characterizing the mechanical properties of BMGs. [9][10][11][12][13][14][15][16][17][18][19][20][21] In general, it is believed that the plastic deformation initiated in BMGs localizes in the narrow zones called shear bands 9) for high strain rates and low temperatures. Bei et al 9) and Zhang et al 10) investigated the effect of the length to diameter aspect ratio on the compression deformation of Zr-based BMGs.…”

Section: Introductionmentioning

confidence: 99%

“…Conner et al 12) measured the mechanical and thermal properties of a Zr 57 Nb 5 Al 10 -Cu 15:4 Ni 12:6 BMG with different oxygen contents. Wesseling et al 13,14) assessed the mechanical behavior of Cu-based BMGs at elevated temperatures and observed significant softening near the glass-transition temperature (T g ).…”

Section: Introductionmentioning

confidence: 99%

Microindentation of a Zr57Ti5Cu20Ni8Al10 Bulk Metallic Glass

et al. 2007

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Using microindentation technique, the indentation behavior of a Zr 57 Ti 5 Cu 20 Ni 8 Al 10 bulk-metallic glass is studied over a range of the indentation load from 200 mN to 5000 mN. For the indentation load larger than 1000 mN, the indentation load-depth curves during unloading display three regions, a) a fast unloading phase at the onset of unloading, b) a linear phase at which the indentation load is proportional to the indentation depth, and c) a slow unloading phase after the linear phase. The size of the linear region increases with the increase in the indentation load, and the slope is independent of the indentation load. The indentation hardness decreases slightly with the increase in the indentation load. The plastic energy dissipated in an indentation cycle is proportional to the 3/2 power of the indentation load. The effect of the indentation loading rate on the indentation behavior is discussed.

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“…4,5) On the other hand, it is reported that the atomic structure and thus the mechanical properties of bulk metallic glass can be transformed by the influence of heat or deformation at high temperature. [6][7][8][9][10] To apply bulk metallic glass to engineering, it is important not only to determine its strength properties and workability but also to propose a way to maintain or improve the mechanical properties after deformation in order to expedite the industrial use of bulk metallic glass. In particular, it is necessary to sustain its original fracture strength even after a thermal process such as annealing or hot working.…”

Section: Introductionmentioning

confidence: 99%

Thermoplastic Deformation and Mechanical Properties of Zr-Based Bulk Metallic Glasses

2007

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The effect of heating and thermoplastic deformation on the fracture stress of Zr 55 Cu 30 Al 10 Ni 5 and Zr 60 Cu 25 Al 10 Ni 5 bulk metallic glass at room temperature (RT) was studied. These metallic glasses were easily crystallized by the influence of heating beyond their upper limit temperature of 685 K and 713 K, respectively. The fracture stress was maintained the strength of material as cast below these temperatures while it decreased easily by crystallization. It was possible to deform these materials below these temperatures. Their strength after thermoplastic deformation depended on the amount of strain, strain rate, and temperature during the deformation. The lower temperature and higher strain rate resulted in high strength after thermoplastic deformation at RT.

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Preliminary assessment of flow, notch toughness, and high temperature behavior of Cu60Zr20Hf10Ti10 bulk metallic glass

Cited by 72 publications

References 27 publications

Glassy steel optimized for glass-forming ability and toughness

Glassy steel optimized for glass-forming ability and toughness

Microindentation of a Zr<SUB>57</SUB>Ti<SUB>5</SUB>Cu<SUB>20</SUB>Ni<SUB>8</SUB>Al<SUB>10</SUB> Bulk Metallic Glass

Thermoplastic Deformation and Mechanical Properties of Zr-Based Bulk Metallic Glasses

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