Assistant professor, The Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
Professor, The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA
Pages: 27 Published: Jan 1997
Dominant inelastic deformation processes of polycrystalline metals in the infinitesimal strain regime are different than those at larger strains. Within the infinitesimal strain regime, dislocation/dislocation interactions and the nucleation and evolution of small-scale dislocation structures such as dislocation cells dominate the strain-hardening character of a face-centered cubic (fcc) material. As the strain transcends the infinitesimal regime, the dominant dislocation substructures become larger macroscopically oriented structures such as dense dislocation walls and microbands. These structures have a profound effect on the mechanical response of the material. The nonrandom crystallographic textures that form at large strain also affect the stress-strain response. With this in mind, interesting and technically significant questions arise concerning the effects of multiaxial nonproportional loading at large strain as well as the effect of a large prestrain on subsequent small-strain multiaxial cyclic deformation behavior. In an attempt to address this question, a matrix of multiaxial large- and small-strain experiments were conducted on Type 304L stainless steel. The large-strain tests consisted of compression, torsion, compression followed by torsion, and torsion followed by tension experiments. A non-proportional small-strain axial-torsional cyclic history was then imposed on material in an annealed state as well as material subjected to an effective torsional plastic prestrain on the order of ¯εp= 100%. Experimental details as well as modeling implications are presented.
polycrystalline metals, multiaxial loading, nonproportional straining, torsion testing, compression testing, sequence tests, large strain, prestrain effects, strain hardening, axial-torsional loading, fatigue (materials), fracture (materials), testing, deformation (materials), multiaxial fatigue
Paper ID: STP16213S