Fracture energy and R-curve behavior of Al{sub 2}O{sub 3}/Mo composites

Journal Article · Mon Jan 05 04:00:00 EST 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00292-9· OSTI ID:616203

Sbaizero, O; Pezzotti, G; Nishida, T ^[1]

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1. Kyoto Inst. of Tech. (Japan). Dept. of Materials

The mechanical properties of a polycrystalline Al{sub 2}O{sub 3} containing increasing fractions of molybdenum particles are examined with particular emphasis placed on the fracture behavior. From the experimental side, both the fracture energy and the rising R-curve behavior of the composites are measured as a function of the volume fraction of the metal dispersoid. A 20 vol% fraction of metal dispersoid was found to markedly enhance the fracture energy of the Al{sub 2}O{sub 3} matrix as well as to make more pronounced its rising R-curve behavior. Microscopic observation of the crack path and fracture surface revealed the presence of stretched metal particles acting as ductile bridging sites behind the crack tip. Assuming crack bridging as the main mechanism contributing to toughening, a Dugdale-like theoretical model which considers the crack faces being shielded by a constant (average) closure stress field is invoked to explain the fracture behavior of the composites.

• OSTI ID: 616203
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 2 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
CRACK PROPAGATION
FRACTURE PROPERTIES
MOLYBDENUM ALLOYS