The effects on fracture toughness of ductile-phase composition and morphology in Nb-Cr-Ti and Nb-Si in situ composites

Journal Article · Tue Oct 01 00:00:00 EDT 1996 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/BF02663850· OSTI ID:417858

Davidson, D L; Chan, K S ^[1]; Anton, D L ^[2]

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1. Southwest Research Inst., San Antonio, TX (United States)
2. United Technologies Research Center, East Hartford, CT (United States)

Niobium-chromium alloys, both single and two phase, were alloyed with titanium in order to enhance fracture toughness and fatigue crack growth resistance. The selection of titanium as an alloying element and the relationship of electronic bonding to toughness are examined. The results indicated that toughness increased with a decreasing number of D + s electrons. Titanium was found to increase the toughness of solid-solution Nb-Cr alloys from {approx}8 to 87 MPa{radical}m, while for the two-phase in situ composites, toughness was increased from {approx}5 to 20 MPa{radical}m, although this is less than expected. Fracture toughness of the composites correlated nonlinearly with the volume fraction of the phases. The evidence suggests that the toughness of the composites is decreased due to fracture of the intermetallic particles and constraint on matrix deformation imposed by the intermetallic. Fracture characteristics of the Nb-Cr-Ti materials are compared to those of Nb-Cr and Nb-Si materials.

• Sponsoring Organization: USDOE
• OSTI ID: 417858
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 27, Issue 10; Other Information: PBD: Oct 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
MORPHOLOGY
FRACTURE PROPERTIES
NIOBIUM ALLOYS
CHROMIUM ALLOYS
SILICON ALLOYS
TITANIUM ALLOYS
INTERMETALLIC COMPOUNDS
CHEMICAL COMPOSITION
SOLID SOLUTIONS
BENDING
PARTICULATES
CRACKS
DUCTILITY