Study of texture and mechanical properties of metallic alloys deformed by shear: equal chanel angular extrusion and assymetric rolling

Abstract

Severe plastic deformation methods applied on metals and alloys activate grain reduction mechanisms, which on their turn result in intense increase of mechanical strength. Moreover, those methods promote change in the original crystallographic texture. We intend to initiate a research line on this topic using two severe plastic techniques, viz, equal channel angular extrusion, and asymmetric rolling. This research line is composed of two sub-projects, which beside possessing technological and practical content (which will be explained in detail ), can produce material suitable to the study of hyper deformation of FCC metals with high and low stacking fault energy: aluminum and austenitic stainless steel respectively. These subprojects are summarized below: 1) Modification of aluminum plates texture aiming to improve their formability (deep drawing capacity) - Al alloys conventionally rolled exhibit an inadequate texture for deep drawing. On the other hand, the consequence of severe plastic deformation is the induction of specific textures which show rotation with respect to the simple shear ideal texture. It was demonstrated that both equal channel angular pressing and asymmetric rolling may induce a more suitable texture for Al alloy sheets. The project will study the formability of the AA1050 deformed by both processes; 2) Increase of the F138 austenitic stainless steel mechanical resistance by means of severe plastic deformation - in this project, Equal Channel Angular Pressing combined with post deformation heat treatments will be used to increase the mechanical strength of a F-138 steel, presently the most used material for orthopedic implants. (AU)