Ductility enhancement from interface dislocation sources in a directionally solidified beta + gamma + gamma-prime Ni-Fe-Al composite alloyA directionally solidified beta + gamma + gamma-prime Ni-Fe-Al in situ composite alloy of composition Ni50Fe30Al20 has been used to investigate the effect of a plastically soft second phase on the mechanical behavior of a B2 ordered intermetallic alloy. This material exhibits extensive plasticity during compressive deformation at room temperature and fails in shear with extensive gamma + gamma-prime lamellar or rod pullout. The material also exhibits about 10 percent tensile elongation to fracture at room temperature, with final fracture that includes substantial necking of the gamma + gamma-prime lamellae or rods. Observation of slip lines and dislocation substructures discloses that the normally brittle beta matrix undergoes extensive plasticity in order to deform compatibly with the more ductile gamma phase. The plasticity of the beta matrix is accomplished by the generation of glissile dislocations into the beta matrix from the beta/gamma interface region and is enhanced because of a favorable beta-gamma orientation relationship for slip transfer. Ductility enhancement from interface-generated mobile dislocations generated from beta-gamma interfaces is compared to that observed in film-coated beta-NiAl single crystals and FeAl polycrystals.
Document ID
19920064226
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Larsen, M. (NASA Lewis Research Center Cleveland, OH, United States)
Misra, A. (NASA Lewis Research Center Cleveland, OH, United States)
Hartfield-Wunsch, S. (Michigan, University Ann Arbor, United States)
Noebe, R. (Michigan, University, Ann Arbor; NASA, Lewis Research Center Cleveland, OH, United States)
Gibala, R. (Michigan, University Ann Arbor, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1990
Subject Category
Metallic Materials
Meeting Information
Meeting: MRS Symposium on Intermatallic Matrix Composites