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Effect of Prestraining on the Brittle-To-Ductile Transition of NiAl Single Crystals

Published online by Cambridge University Press:  15 February 2011

S. Shrivastava  and
F. Ebrahimi
S. Shrivastava
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611
F. Ebrahimi
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611
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Abstract

The brittle-to-ductile transition (BDT) has been established for NiAl single crystals as evaluated by fracture toughness testing and also the effects of prestraining on the brittle-to-ductile transition temperature (BDTT) have been investigated. Specimens were prestrained to a 10% plastic strain level at 200°C under tension prior to toughness testing. The BDT of the prestrained specimens was compared to that of the as homogenized specimens. The results have revealed the occurrence of two competing effects upon prestraining: (1) an increase in dislocation sources causing a difficulty in micro-crack initiation and resulting in an increase in toughness at low temperatures, and (2) an increase in the flow stress resulting in an increase in BDT temperature. The crack initiation and propagation mechanisms were also analyzed and have been discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 393
Copyright
Copyright © Materials Research Society 1997

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References

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