Abstract
Fracture toughness tests were carried out using different Zr composition in Zr-Cu-Al based bulk metallic glasses (BMGs) and heat-treated those just under the glass transition temperature (T g) in order to examine the effects of Zr composition and heat-treatment on the fracture toughness (K Q; fracture toughness including the values under unsatisfying the plane strain condition). Zr 50Cu 40Al 10, Zr 55Cu 35Al 10 and Zr 60Cu 30Al 10 BMGs fabricated by a tilt ark casting method were used. Heat-treatments were done for 90 minutes just under the T gs of each BMG. Tests were conducted based on ASTM E399. Compact type specimen was used (thickness = 2.3, 2.0 mm, thickness : width =1:4). Fatigue pre-crack was induced under ΔK less than 6 MPa ̇ m 1/2 by a servohydraulic fatigue machine and the fracture toughness test was done by using the same machine. The K Q dominantly increased with increasing the Zr composition. The K Q in heat-treated BMGs decreased in comparison with that in unheat-treated BMGs in all Zr composition. In the BMG of the high Zr composition, however, the decrease was small after heat-treatment, and the K Q showed enough high values. In heat-treated BMGs, the dispersion of K QS did not become small, but fatigue pre-cracks were induced more vertical against the loading axis and less bifurcation than those in unheat-treated BMGs.
Original language | English |
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Pages (from-to) | 730-735 |
Number of pages | 6 |
Journal | Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals |
Volume | 71 |
Issue number | 9 |
DOIs | |
Publication status | Published - 2007 Sep |
Externally published | Yes |
Keywords
- Bulk metallic glass
- Fracture toughness
- Heat-treatment
- Hypoeutectic composition
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys
- Materials Chemistry