Open-die forging of structurally porous sandwich panels

Citation
Dm. Elzey et Hng. Wadley, Open-die forging of structurally porous sandwich panels, MET MAT T A, 30(10), 1999, pp. 2689-2699
Citations number
14
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science",Metallurgy
Journal title
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
ISSN journal
10735623 → ACNP
Volume
30
Issue
10
Year of publication
1999
Pages
2689 - 2699
Database
ISI
SICI code
1073-5623(199910)30:10<2689:OFOSPS>2.0.ZU;2-H
Abstract
Structurally porous metal sandwich panels consisting of dense face sheets a nd porous cores of controlled relative density can be manufactured by trapp ing inert gas during hot isostatic pressing and modifying its distribution via subsequent thermomechanical forming. A plane-strain solution for analyz ing the open-die forging of such a plastically compressible sandwich panel is developed. An effective yield potential for the face sheet/core sandwich is constructed from the Mises yield criterion for the rigid-plastic face s heet and Doraivelu et al's density-dependent yield function for the compres sible core. This effective constitutive response is used in a classical "sl ab" analysis of open-die forging. The analysis predicts the upsetting force and the distributions of pressure, core relative density, and average stre sses within both the face sheet and the core. During upsetting, a zone of f ully constrained material (i.e., with zero lateral strain) is predicted to occur at the center of the workpiece, and this densifies first. A densifica tion front then advances laterally from the panel center toward the outer e dges. The nonuniform densification complicates the use of forging for the p roduction of components requiring a uniform density core.