Increased Toughness of Zirconium-Based Bulk Metallic Glasses Tested under Mixed Mode Conditions

Abstract

The effects of mixed mode loading on the fracture behavior of Zr-based bulk metallic glasses (BMGs) (Vitreloy I and Vitreloy 106) were investigated. Mixed mode I/II and mixed mode I/III fracture conditions were tested using both notched and fatigue-precracked specimens. Fully amorphous samples exhibited tremendous increases in fracture energy with the application of mixed mode loading, while partially crystalline samples exhibited more modest increases. A comparison to the behavior of other material systems (e.g., polymers, ceramics, crystalline metals, and composites) illustrates the tremendous increase in fracture energy exhibited by these BMGs under mixed mode loading conditions.

Locating bulk metallic glasses with high fracture toughness: Chemical effects and composition optimization

“…4e. While the notch toughness, when measured in the same way and in the same geometry, is useful to compare the toughness of different BMGs (as we have done in some plots in this paper), to measure more rigorously the intrinsic material fracture toughness one needs to exclude the blunting effect of the notch root radius [7,29]. The ZT1 BMG was therefore further tested using fatigue pre-cracked samples.…”

Spiral fracture in metallic glasses and its correlation with failure criterion

“…This confirms that the failure strength in Vitreloy 1 is only moderately normal stress/ pressure-dependent when failure occurs by shear. However, inclusion-initiated failure has been shown to change this dependence [17].…”

“…pressure independent) might be appropriate. All of these previous works highlight the importance of continuing to examine the effects of changes in stress state and loading mode, as these have been observed to affect the deformation and fracture toughness, as shown by others [15][16][17].…”

Toughness of Bulk Metallic Glasses

“…Similarly, the Zr61Ti2Cu25Al12 glass has toughness of 130 ± 20 MPa.m 1/2 and a rising R-curve [32] which arises due to extensive shear banding at the crack tip that leads to crack deflection and a change in the local loading (at the crack tip) from pure mode I to mixed mode I/II. Mixed mode loading is known to enormously increase the toughness values [33]. Although the above toughness data are not strictly KIc values, it is impressive that certain compositions are able to show such profuse shear banding so as to change the loading mode.…”