Deformation and fracture behavior of metallic glass-metal matrix composites

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5976424

Leng, Yang

The objectives of this study are: to investigate the deformation and fracture behavior of metallic glass in metal matrix composites as the behavior is affected by different geometries and by stress conditions, and to analyze the behavior with theoretical and numerical approaches in order to discover the mechanisms controlling such behavior. Metallic glass-metal matrix composites were fabricated with a Ni base glass (Ni{sub 91}B{sub 2}Si{sub 7}) and brass (Cu{sub 70}Zn{sub 30}). Tensile properties and crack growth resistance of the composites were studied. Tensile ductility of the glass in the composites was enhanced via development of multiple shear bands during tensile deformation. The brass matrix provided a mechanical restraint for shear band instability, and enhanced ductility of metallic glass depended on the matrix strengths. It is found that the secondary shear band initiation is controlled by both internal and external factors. Finite element methods were used to investigate the external stress concentrations and experimental studies determined the internal properties of the metallic glass which refers to shear band strength distributions. The initiation sites of the secondary shear bands was semi-quantitatively predicted using the combined results from the external and internal analysis. A stress/strain concentration model was also used to predict phenomenological tensile modes of the composites, and it agrees qualitatively with experimental observations. The metallic glass crack growth behavior was examined in the composites and in the monolithic form. The composite structure significantly increases the crack growth resistance, and changes metallic glass crack growth mode from catastrophic to stable one. Such behavior was expressed with R curves and discussed in terms of extrinsic and intrinsic toughening mechanisms. It is found that a bridging effect make a major contribution of extrinsic toughening.

• Research Organization: Virginia Univ., Charlottesville, VA (USA)
• OSTI ID: 5976424
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BRASS
MECHANICAL PROPERTIES
METALLIC GLASSES
COMPARATIVE EVALUATIONS
COMPOSITE MATERIALS
CRACK PROPAGATION
DEFORMATION
DUCTILITY
FINITE ELEMENT METHOD
FRACTURE PROPERTIES
MATHEMATICAL MODELS
NICKEL BASE ALLOYS
STRESS ANALYSIS
TENSILE PROPERTIES
ALLOYS
COPPER ALLOYS
COPPER BASE ALLOYS
MATERIALS
NICKEL ALLOYS
NUMERICAL SOLUTION
ZINC ALLOYS
360603* - Materials- Properties