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Internal stress superplasticity in anisotropic polycrystalline zinc and uranium

Journal Article · · Metall. Trans., A; (United States)
OSTI ID:6977461

Internal stress superplasticity is assessed in powder metallurgy and wrought polycrystalline Zn and in polycrystalline ..cap alpha..-U. These materials are anisotropic in their thermal expansion coefficients, and, as a result, internal stresses are generated during thermal cycling. A creep model is developed based on the contribution of internal stress to the enhancement and inhibition of normal plastic flow. This creep model, which has no disposable parameters, is shown to describe quantitatively the flow behavior of anisotropic materials under thermal cycling conditions, and correctly predicts the attainment of Newtonian flow characteristics at low stresses. It is predicted that certain polycrystalline ceramics can be made superplastic in tension when thermally cycled under small applied stress.

Research Organization:
Signetics Corp., 811 East Arques Avenue, Sunnyvale, CA (US)
OSTI ID:
6977461
Journal Information:
Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 18A:3; ISSN MTTAB
Country of Publication:
United States
Language:
English