Dislocation structures of Ni/sub 3/(Al,Nb) single crystals fatigued at ambient and elevated temperatures

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(87)90085-X· OSTI ID:5574411

Bonda, N R; Pope, D P; Laird, C

In order to support companion studies of the cyclic stress-strain response of Ni/sub 3/(Al,Nb) crystals, the dislocation structures of crystals cycled at ambient temperature, 400 and 700/sup 0/C, have been studied by TEM. Unit or dipolar screw dislocations were observed in high density for the two lower temperatures. These results support the theory of cross-slip-induced friction stress on the dislocations, which explains the anomalous increase of flow stress with temperature as well as the tension-compression asymmetry in the cyclic results. For crystals tested at 700/sup 0/c, the character of the dislocation structure changes and includes a higher density of edge dislocations, consistent with saturation of the temperature effect on the flow stress and the onset of cube slip.

• Research Organization: Dept. of Metallurgical Engineering, Ohio State Univ., Columbus, OH 43210
• OSTI ID: 5574411
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 35:9; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ALUMINIUM ALLOYS
AMBIENT TEMPERATURE
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
DISLOCATIONS
EDGE DISLOCATIONS
FATIGUE
HIGH TEMPERATURE
LINE DEFECTS
MECHANICAL PROPERTIES
MONOCRYSTALS
NICKEL ALLOYS
NIOBIUM ALLOYS
STRESSES
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE EFFECTS
THERMAL FATIGUE
THERMAL STRESSES