Browsing by Author "Ruano, O. A."
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Item Influence of thermomechanical processing on superplastic forming of Mg-Al alloys(2007-04) Pérez-Prado, M. T.; Del Valle, J. A.; Salort, F.; Peñalba, F.; Gómez, X.; Ruano, O. A.; EXTREMATThe aim of this paper is to study the influence of the initial microstructure of several Mg-Al alloys on their superplastic formability and on their post-forming microstructure and mechanical properties. Various thermomechanical processing routes, such as annealing, conventional rolling, severe rolling and cross rolling, were used in order to fabricate AZ31 and AZ61 alloys with different grain sizes. These materials were then blow formed into a hat shaped die. It was found that the processing route has only a small effect in the formability of Mg-Al alloys or on the postforming microstructures and properties due to rapid dynamic grain growth taking place at the forming temperatures. Nevertheless, good formability is achieved as a result of the simultaneous operation of grain boundary sliding and crystallography slip during forming.Item Mechanical properties and forming behavior of a type 9%Cr steel containing 2%W(Trans Tech Publications Ltd, 2010) Peñalba, F.; Gómez, X.; Allende, R.; Carsí, M.; Ruano, O. A.; Chandra, Tara; Chandra, Tara; Chandra, Tara; Wanderka, N.; Wanderka, N.; Wanderka, N.; Reimers, Walter; Reimers, Walter; Reimers, Walter; Ionescu, M.; Ionescu, M.; Ionescu, M.; EXTREMATThe possibilities to improve the properties of steels for tubes exposed at high temperatures are explored. The mechanical properties and forming behavior of an experimental casting of type 9Cr-ferritic steels, P92, containing 2%W, are studied. The hardenability was determined by means of continuous cooling diagrams associated with hardness measurements and microstructure observations. Tensile tests from room temperature to 650°C were carried out to determine the variation of the strength and ductility in this temperature range. In addition, Charpy impact tests were conducted to characterize the toughness of the steel and the ductile-brittle transition temperature. Finally, hot torsion tests at various temperatures and strain rates were carried out and the generalized stresses and strains to rupture for each test are determined. With these data forming stability maps were generated to characterize the best forming conditions.