No abstract

In-situ neutron diffraction combined with the incremental deformation at room temperature has been used to provide a measure of the internal stress and internal resistance generated by the prior inelastic deformation at high temperature in an austenitic stainless steel. Interactions between the internal stress and internal resistance are considered explicitly by using the proposed measurement technique.The magnitude of the intergranular internal stress is found to be a function of the total inelastic strain created by high temperature prior deformation. The deviation from linearity observed in the lattice strain response is used to derive the microscopic internal resistance, but a crystal plasticity model is required to infer the absolute value.The macroscopic internal resistance is shown to be consistent with Taylor hardening.A refined internal state concept is proposed based on the Kocks-Mecking model to provide a further step to predict the inelastic deformation.

. (2015) Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material. Acta Materialia, http://dx.doi.org/10.1016/j.actamat. .11.021 DOI 10.1016/j.actamat.2014.11.021 ISSN 1359 Publisher: Elsevier Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. This document is the author's post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it. AbstractThe role of misfit stress on kinematic hardening under reversed straining of a Type 316H austenitic stainless steel has been investigated by using the neutron diffraction technique combined with in-situ deformation. Initial misfit stresses, often referred to an intergranular internal stresses, were created by the tensile pre-straining at high temperature. The misfit stresses at the length-scale of grain families, measured by neutron diffraction, were shown to be a function of the magnitude of the tensile prestrain. The pre-strained specimens were further subjected to either continued (tensile) straining or reversed (compressive) straining at room temperature. In-situ neutron diffraction measurements were undertaken to monitor the change of the misfit stresses during loading. The macroscopic stress-strain behaviour was used to derive isotropic and kinematic hardening stresses developed in the pre-strained specimens. Resultsshow that the change of the transient softening stress towards a zero value is accompanied by a decrease in the change of the misfit stresses. A multi-scale selfconsistent model has been developed to assist in understanding the measured change of the misfit stresses when subjecting the material to strain reversal. An important conclusion is that the origin of the kinematic hardening of Type 316H austenitic stainless steel arises from the misfit stress between grains.