Anomalous elongation behavior of stoichiometric NiAl single crystals at intermediate temperatures

Journal Article · Wed Mar 31 23:00:00 EST 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90150-Q· OSTI ID:6239886

Takasugi, T; Kishino, J; Hanada, S ^[1]

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1. Tohoku Univ., Sendai (Japan). Inst. for Materials Research

The tensile deformation behavior and the associated deformation microstructures of stoichiometric NiAl single crystals were investigated in various experimental conditions of crystal orientation, temperature and strain rate. Consequently, the anomalously large elongations were observed at intermediate temperatures, i.e. at 0.35-0.4 T[sub m], depending on crystal orientation and strain rate. At low temperatures, the stress exponent of 8.3 and the apparent activation energy of 118 kJ/mol were measured. The glide motion of the (100) dislocations (i.e. the work hardening) was dominant. At high temperatures, the stress exponent of 5.0 and the apparent activation energy of 157 kJ/mol were measured. The climb motion of the (100) dislocations (i.e. the recovery) was dominant. At intermediate temperatures, the values of these parameters were intermediate and continuously varied. It was shown that the glide motion and the climb motion of the (100) dislocations were evenly dominant. Based on the observed mechanical behavior and dislocation structures, the micro-mechanism responsible for the anomalously large elongation operative at intermediate temperatures was suggested.

• OSTI ID: 6239886
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 41:4; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
HARDENING
INTERMETALLIC COMPOUNDS
LINE DEFECTS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES