SYMPOSIA PAPER Published: 01 January 1972

Toughness of Filamentary Boron/Aluminum Composites


An exploratory study was carried out to determine whether, in terms of the definitions and test procedures developed for alloys, valid fracture toughness values could be measured for highly anisotropic and heterogeneous boron/aluminum composites. The mechanical test results were correlated with acoustic emissions from filament breakage, with fractography, and with high-speed movies of surface deformation and crack growth.

The plane strain fracture toughness, KIc, parallel to the filament axis of center notched specimens of 6061 aluminum-30 volume percent boron was determined to be ∼30,000±4000 psi √in. Filament pullout contributed negligibly to the fracture toughness of the composite. The minimum plate thickness, in terms of the plastic enclave size factor (KIcy) necessary to achieve plane strain conditions is about the same as that recommended for metals. The results indicate that conventional concepts of fracture toughness can be applied to filament reinforced metals to provide engineering design data.

Author Information

Hancock, JR
Midwest Research Institute, Kansas City, Mo.
Swanson, GD
Midwest Research Institute, Kansas City, Mo.
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Developed by Committee: D30
Pages: 299–310
DOI: 10.1520/STP27754S
ISBN-EB: 978-0-8031-4606-8
ISBN-13: 978-0-8031-0134-0