Unconstrained and constrained tensile flow and fracture behavior of an Nb-1.24 at. pct Si alloys

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02670764· OSTI ID:87696

Mendiratta, M G; Goetz, R ^[1]; Dimiduk, D M ^[2]; Lewandowski, J J ^[3]

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1. UES, Inc., Dayton, OH (United States)
2. Wright Labs., Wright-Patterson AFB, OH (United States)
3. Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Metallurgy and Materials Science

The unnotched and notched tensile behavior of the {beta}-phase constituent (Nb with Si in solid solution) of the (Nb)/Nb{sub 5}Si{sub 3} composite has been investigated at room temperature and {minus} 196 C. At room temperature, the unnotched tensile behavior comprises significant strengthening due to Si, low strain-rate sensitivity, low strain hardening, extensive ductility, and ductile microvoid coalescence fracture, even at strain rates as high as 1.1 s{sup {minus}1}. At {minus}196 C, the unnotched alloy exhibited much higher strength, good ductility, and cleavage fracture. At room temperature, the notched specimens exhibited cleavage like fracture with significant plasticity, and at {minus}196 C, they exhibited cleavage like fracture with much lower plasticity at the notch. A finite-element analysis (FEA) of stress and strain fields in the vicinity of the notch root, together with unnotched tensile behavior, indicates that plasticity plays an important role in nucleating cracks, while the high-axial tensile stress component governs crack propagation. These results are used to rationalize the observed toughening and fracture behavior of a (Nb)/Nb{sub 5}Si{sub 3} composite.

• Sponsoring Organization: USDOE
• OSTI ID: 87696
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 7 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMBIENT TEMPERATURE
COMPOSITE MATERIALS
FRACTURE PROPERTIES
NIOBIUM ALLOYS
NIOBIUM SILICIDES
TEMPERATURE RANGE 0065-0273 K
TENSILE PROPERTIES