Ductile-reinforcement toughening in [gamma]-TiAl intermetallic-matrix composites: Effects on fracture toughness and fatigue-crack propagation resistance

Journal Article · Tue Mar 01 00:00:00 EST 1994 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(94)90285-2· OSTI ID:5046149

Venkateswara Rao, K T; Ritchie, R O ^[1]; Odette, G R ^[2]

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1. Univ. of California, Berkeley (United States). Dept. of Materials Science and Mineral Engineering
2. Univ. of California, Santa Barbara (United States). Materials Dept.

The influence of the type, volume fraction, thickness and orientation of ductile phase reinforcements on the room temperature fatigue and fracture resistance of [gamma]-TiAl intermetallic alloys is investigated. Large improvements in toughness compared to monolithic [gamma]-TiAl are observed in both the TiNb- and Nb-reinforced composites under monotonic loading. Toughness increases with increasing ductile phase content, reinforcement thickness and strength; orientation effect are minimal. Crack-growth behavior is characterized by steep resistance curves primarily due to crack trapping/renucleation and extensive crack bridging by the ductile-phase particles. In contrast, under cyclic loading the influence of ductile phases on fatigue resistance is strongly dependent upon reinforcement orientation. Compared to monolithic [gamma]-TiAl, improvements in fatigue-crack growth resistance are observed in TiNb-reinforced composites only in the face (C-L) orientation; crack-growth rates for the edge (C-R) orientation are actually faster in the composite. In comparison, Nb-particle reinforcements offer less toughening under monotonic loading but enhance the fatigue properties compared to TiNb reinforcements under cyclic loading.

• OSTI ID: 5046149
• Journal Information: Acta Metallurgica et Materialia; (United States), Vol. 42:3; ISSN 0956-7151
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
COMPOSITE MATERIALS
NIOBIUM ALLOYS
TITANIUM BASE ALLOYS
DUCTILITY
DYNAMIC LOADS
FATIGUE
FRACTURE PROPERTIES
ALLOYS
MATERIALS
TENSILE PROPERTIES
TITANIUM ALLOYS
360603* - Materials- Properties
360602 - Other Materials- Structure & Phase Studies