Acta Materialia 50 (2002) 1627–1638 www.actamat-journals.com Lattice strain evolution during cyclic loading of stainless steel T. Lorentzen 1,a , M.R. Daymond b,* , B. Clausen 2,c , C.N. Tome ´ d a Materials Research Department, Risø National Laboratory, Roskilde 4000, Denmark b ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK c LANSCE-12, Los Alamos National Laboratory, Los Alamos, NM 87545, USA d MST-8, Los Alamos National Laboratory, Los Alamos, NM 87545, USA Received 4 September 2001; received in revised form 28 December 2001; accepted 28 December 2001 Abstract A uniaxial tension/compression test specimen was cycled between fixed total strain limits of ±0.4% for eight success- ive cycles. The sample was loaded using a dedicated Instron hydraulic load frame on the ENGIN station of the PEARL beam line at the ISIS facility of the Rutherford Appleton Laboratory. The load frame was aligned to allow simultaneous monitoring of longitudinal and transverse lattice strain components. There was a strong experimental hkl-dependency of the lattice strain response in both the effective stiffness and in the lattice strain loop hysteresis. The experimental data were compared with numerical predictions obtained from a self-consistent elasto-plastic model for the simulation of polycrystal deformation. A cyclic hardening law was developed and implemented into the modelling scheme, providing theoretical predictions in good agreement with experimental observations.  2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. Keywords: Bauschinger effect; Neutron diffraction; Elasto-plastic self-consistent model 1. Introduction The deformation of polycrystalline materials has constituted an important branch of materials science for more than 60 years. Throughout this * Corresponding author. Tel.: +44-1235-445434; fax; +44- 1235-445720. E-mail address: mark.daymond@rl.ac.uk (M.R. Daymond). 1 Currently at DanStir ApS, CAT Science Park, Postboks 30, Roskilde 4000, Denmark. 2 Currently at Department of Materials Science, California Institute of Technology, Pasadena, CA 91125, USA. 1359-6454/02/$22.00  2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. PII:S1359-6454(02)00029-0 period the major focus has been on macroscopic flow curve prediction, texture simulation and yield loci calculation. In recent years the focus has also been directed towards the prediction of the devel- opment of lattice strains for differently oriented grains within the polycrystal. This area of interest can largely be attributed to the increased use of neutron diffraction as a tool for studying the micromechanics of polycrystalline aggregates, and for engineering applications such as residual stress characterization [1]. The study of residual stress generation in polycrystals using neutron diffraction has a two- fold aim. First, neutron diffraction is especially