Fracture Toughness of Amorphous Metals and Composites

2002 ◽  
Vol 754 ◽  
Author(s):  
J.J. Lewandowski ◽  
A.K. Thurston ◽  
P. Lowhaphandu
Keyword(s):  
Fracture Toughness ◽  
Metallic Glasses ◽  
Shear Banding ◽  
Notch Toughness ◽  
Body Centered Cubic ◽  
Temperature Dependent ◽  
Notch Radius ◽  
Glass Composites ◽  
Planar Crack ◽  
Crack Bifurcation

ABSTRACTThe effects of changes in notch radius on the toughness of two different Zr-based bulk metallic glasses have been determined. It is shown that increases in notch radius produce large increases to the toughness, accompanied by extensive shear banding and crack bifurcation. The fracture toughness of twenty (20) fatigue precracked specimens exhibiting planar crack growth were in the range 20.3 ± 6.7 MPa√m for the two Zr-based glasses. Increasing the notch radius to 110 μm produced notch toughness in the range 95.3 ± 8.3 MPa√m for nine (9) tests on Vitreloy I, well in excess of that typically observed in most structural materials. Toughness tests conducted on two fatigue precracked specimens of Vitreloy I at 77 K produced values for fracture toughness that were in the range 17.9 ± 2.7 MPa√m, similar to that obtained at 298 K. The fatigue precracked fracture toughness of metallic glass composites containing large crystalline regions of a body centered cubic Zr-Ti-Nb alloy were in the range 29–42 MPa√m, but the values were temperature dependent over the range 148 K to 500 K. Fracture surfaces were analyzed via Scanning Electron Microscopy (SEM).

scholarly journals Tension-Tension Fatigue Behavior of High-Toughness Zr61Ti2Cu25Al12 Bulk Metallic Glass

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2815
Author(s):  
Yu Hang Yang ◽  
Jun Yi ◽  
Na Yang ◽  
Wen Liang ◽  
Hao Ran Huang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Shear Band ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Fatigue Resistance ◽  
Metallic Glasses ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Bulk Metallic Glasses ◽  
High Toughness

Bulk metallic glasses have application potential in engineering structures due to their exceptional strength and fracture toughness. Their fatigue resistance is very important for the application as well. We report the tension-tension fatigue damage behavior of a Zr61Ti2Cu25Al12 bulk metallic glass, which has the highest fracture toughness among BMGs. The Zr61Ti2Cu25Al12 glass exhibits a tension-tension fatigue endurance limit of 195 MPa, which is higher than that of high-toughness steels. The fracture morphology of the specimens depends on the applied stress amplitude. We found flocks of shear bands, which were perpendicular to the loading direction, on the surface of the fatigue test specimens with stress amplitude higher than the fatigue limit of the glass. The fatigue cracking of the glass initiated from a shear band in a shear band flock. Our work demonstrated that the Zr61Ti2Cu25Al12 glass is a competitive structural material and shed light on improving the fatigue resistance of bulk metallic glasses.

Temperature dependent fracture toughness of KNN-based lead-free piezoelectric ceramics

2019 ◽  
Vol 174 ◽  
pp. 369-378 ◽  
Author(s):  
Yingwei Li ◽  
Yixuan Liu ◽  
Paul-Erich Öchsner ◽  
Daniel Isaia ◽  
Yichi Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
Temperature Dependent

Erratum to: “Size-dependent fracture toughness of bulk metallic glasses” [Acta Mater. 70 (2014) 198–207]

2014 ◽  
Vol 80 ◽  
pp. 507 ◽  
Author(s):  
Bernd Gludovatz ◽  
Steven E. Naleway ◽  
Robert O. Ritchie ◽  
Jamie J. Kruzic
Keyword(s):  
Fracture Toughness ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Size Dependent ◽  
Acta Mater

On notch fracture mechanics

2021 ◽  
Vol 87 (2) ◽  
pp. 56-64
Author(s):  
G. Pluvinage
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Plastic Zone ◽  
Fracture Resistance ◽  
Notch Radius ◽  
Notch Stress Intensity Factor ◽  
Blunt Notch ◽  
Notch Stress

Different stress distributions for an elastic behavior are presented as analytical expressions for an ideal crack, a sharp notch and a blunt notch. The elastic plastic distribution at a blunt notch tip is analyzed. The concept of the notch stress intensity factor is deduced from the definition of the effective stress and the effective distance. The impacts of the notch radius and constraint on the critical notch stress intensity factor are presented. The paper ends with the presentation of the crack driving force Jρ for a notch in the elastic case and the impact of the notch radius on the notch fracture toughness Jρ,c. The notch fracture toughness Jρ,c is a measure of the fracture resistance which increases linearly with the notch radius due to the plastic work in the notch plastic zone. If this notch plastic zone does not invade totally the ligament, the notch fracture toughness Jρ,c is constant. This occurs when the notch radius is less than a critical one and there is no need to use the cracked specimen to measure a lower bound of the fracture resistance.

scholarly journals Prediction of Characteristic Length and Fracture Toughness in Ductile-Brittle Transition

2008 ◽  
Author(s):  
Z. X. Wang ◽  
H. M. Li ◽  
Y. J. Chao ◽  
P. S. Lam
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Characteristic Length ◽  
Crack Tip ◽  
Critical Distance ◽  
Transition Regime ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Element Method

Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from −160 to −45 °C within the ductile-brittle transition regime. As many researchers have shown, the failure stress (σf) of the material could be approximated as a constant. The characteristic length, or the critical distance (rc) from the crack tip, at which σf is reached, is shown to be temperature dependent based on the crack tip stress field calculated by the finite element method. With the J-A2 two-parameter constraint theory in fracture mechanics, the fracture toughness (JC or KJC) can be expressed as a function of the constraint level (A2) and the critical distance rc. This relationship is used to predict the fracture toughness of A533B-1 in the ductile-brittle transition regime with a constant σf and a set of temperature-dependent rc. It can be shown that the prediction agrees well with the test data for wide range of constraint levels from shallow cracks (a/W = 0.075) to deep cracks (a/W = 0.5), where a is the crack length and W is the specimen width.

scholarly journals Temperature-dependent yield asymmetry between tension and compression in metallic glasses

2012 ◽  
Vol 61 (3) ◽  
pp. 036201
Author(s):  
Chen Yan ◽  
Jiang Min-Qiang ◽  
Dai Lan-Hong
Keyword(s):  
Metallic Glasses ◽  
Temperature Dependent ◽  
Tension And Compression

Local atomic environment and shear banding in metallic glasses

2018 ◽  
Vol 155 ◽  
pp. 129-135 ◽  
Author(s):  
Marcela Tercini ◽  
Roberto Gomes de Aguiar Veiga ◽  
Alejandro Zúñiga
Keyword(s):  
Metallic Glasses ◽  
Shear Banding ◽  
Local Atomic Environment
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