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Shi, Heying
(1990).
DOI: https://doi.org/10.21954/ou.ro.0000f0d7
Abstract
Solid and powdered Al-2014 alloy extrusions, heat transfer during compaction, temperature changes during extrusion, microstructures of extrusion products, hot torsion and plane strain compression tested specimens have been extensively investigated. Estimation of maximum and minimum pressure allows the prediction of the possibility of an extrusion and the amount of heat transferred from mechanical work to be obtained.
Temperature changes during extrusion have a major effect on the extrusion pressure, microstructure and quality of the products. Temperature changes are mainly in two stages: compaction and steady-state and a numerical model of these stages has been developed.
Hot torsion and plane strain compression data has been analysed and this data is used to predict the shear stress at any temperature and strain rate by using hot working theory. The minimized extrusion pressure may then be obtained by upper-bound solution.
Microstructures of hot torsion, plane strain compression and extrusion have been extensively examined. ATLASES of microstructures at hot working condition for both solid and powdered material have been created.
The thermal model has been shown to be essential for the fundamental prediction of hot shortness limits and for the comparison of microstructures between extrusion and metal working tests.