Fracture toughness in Zr-based bulk metallic glass

Kazutaka Fujita, Nobuyuki Nishiyama, Kenji Amiya, Tao Zhang, Hisamichi Kimura, Akihisa Inoue

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Fracture toughness (KIC) was investigated for bulk metallic glass (BMG) materials Zr55Cu30Ni5Al 10 at % fabricated by a suction casting method (material Su) and squeeze casting method (material Sq), and Zr65Cu15Ni 10Al10 at % fabricated by a powder extrusion method (material P). The KIC value in the specimen with a notch plane normal to the boundary plane of molten metal was larger than that parallel to the boundary one. In the specimens with the notch plane normal to the boundary plane, the KIC of a full glassy material Su and a partially crystallized material Su showed a large value about 40 MPa√ m and a little small value about 31 MPa√m, respectively. The KIC of a nearly full-crystallized material Sq showed a small value about 1 lMPa√m. The KIC of a full glassy material P showed a value about 17MPa√m. In the material Su, long bent slip lines (length; ~ several hundred μ m) at the fatigue crack tip were observed on the specimen surface. The Plane-strain type slip lines and the discrete crack tip openings (width; about 5-10μm) like the stretch zone in crystalline alloys were observed along the fatigue crack front on the fracture surface. Near the specimen surfaces, cracks propagated along the long bent slip lines. The crack length was about two times longer than the plastic zone size calculated under the plane-stress condition. There was a tendency that the KIC value in the 2.3mm thickness plate was larger than that in the lmm thickness plate. This tendency was reverse to the results of crystalline alloys.

Original languageEnglish
Pages (from-to)323-326
Number of pages4
JournalJournal of Metastable and Nanocrystalline Materials
Publication statusPublished - 2005


  • Bulk metallic glass
  • Fractography
  • Fracture mechanics
  • Fracture toughness
  • Stretch zone

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Science(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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