Effetti del percorso di deformazione sull'acciaio inossidabile austenitico AISI 316L deformato plasticamente ad alte temperature

摘要

In most thermo-mechanical processes, complex states of stress are developed within materials because of the imposed deformation geometry and friction conditions and, as a consequence, the strain path is not proportional at any time through the process. Finite Element Method (FEM) models are commonly employed in industry to design optimal process route and predict the final material micro structure that defines the mechanical properties of the final industrial products. However, previous investigations have reported significant discrepancies between FEM model results and actual materials behaviour, particularly when microstructure prediction has been required. Such investigations have suggested that the reasons of the discrepancies are why the constitutive equations used in the FEM models are based on equivalent strains and the strain paths followed within the materials during deformations are not accounted for, although, in fact, flow behaviour and microstructure evolution of materials have been reported to be influenced by strain paths. Hence, the investigation on the effects of strain paths on material behaviour is both of scientific and commercial significant interest, because of necessary exploration into the intrinsic plastic deformation mechanisms and the potential industrial applications.