Accession Number:

ADA000373

Title:

Influence of Stress on Precipitation and Coarsening in Alloys.

Descriptive Note:

Final rept.,

Corporate Author:

UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES ELECTRONIC SCIENCES LAB

Personal Author(s):

Report Date:

1974-09-01

Pagination or Media Count:

20.0

Abstract:

Scanning and transmission electron microscopy of precipitate morphologies of normalized and stress-aged Udimet 700 and Ni9 Al wt pct alloys were studied. In both alloys, rods and plates are formed by a coarsening process involving shape change and agglomeration. All experimental observations, the stress aging behavior of Mar-M200, the NiAl-Cr eutectic and the various omega containing titanium-base alloys can be understood on the basis that the morphology forms, and minimizes a free energy including interfacial energy, residual strain energy and interaction energy terms. A method of estimating the residual strain energy and interaction energy of an infinite plate, infinite rod and cuboidal composite has been developed. A theory of diffusional creep has been developed for binary metallic solid-solutions subjected to a uniform uniaxial state of stress. Several predictions of the theory have been confirmed in NiCr and NiW solid solutions.

Subject Categories:

  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE