Structural ledges at precipitate/matrix interfaces in a (Ni, Co) superalloy: atomic structures and elastic fields

• Published in: Ultramicroscopy Vol. 51; no. 1; pp. 270 - 281
• Main Authors: Loubradou, M., Pénisson, J.M., Bonnet, R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1993; Elsevier Science
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Defects and impurities: doping, implantation, distribution, concentration, etc; Electron, ion, and scanning probe microscopy; Exact sciences and technology; Linear defects: dislocations, disclinations; Metals. Metallurgy; Microscopic defects (voids, inclusions, etc.); Physics; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Transmission, reflection and scanning electron microscopy(including ebic); Thin films; Dislocation network; Misfit dislocations; Solid-solid interfaces; Defect structure; Experimental study; Microstructure; Superalloys; TEM; Precipitates; High-resolution methods
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/0304-3991(93)90153-O

The broad faces of plate-like DO 19 precipitates of a (Ni, Co) base superalloy are decorated with triangular networks of linear singularities (LS's) accomodating the 2.5% isotropic length misfit in the atomically dense planes (111) fcc∥(0001) DO19. High-resolution electron microscopy images depict the detailed atomic cores of two of these LS's and show that they are associated with ledges of two (111) spacings in height. The elastic fields surrounding the LS's are analyzed by using both multislice computations and the Somigliana dislocation model in anisotropic elasticity theory. As a result, the Burgers-vector content of the observed ledges is found to be 1 6 〈112〉 vectors.