Hardening (metallurgy)

About: Hardening (metallurgy) is a research topic. Over the lifetime, 25584 publications have been published within this topic receiving 376012 citations.

Latent hardening in single crystals. II. Analytical characterization and predictions

Abstract: Constitutive equations are developed that characterize the multiple-slip behaviour of crystalline materials at low temperature. A matrix of instantaneous hardening moduli that relate the rate of hardening on each slip system to all slip-rates is proposed based upon well-known observations and the latent hardening experiments reported in Part I. In general, these moduli depend on the history of slips. Simulations of various behaviours are presented for FCC single crystals (copper) that are in good agreement with observations. These include, for example, stress-strain curves in a uniaxial loading test, hardening rate variations with respect to initial orientation, latent hardening, tensile overshoot and secondary slips. Numerical calculations are facilitated using an extremum principle and a modified quadratic programming algorithm.

A kinematic hardening constitutive model for natural clays with loss of structure

Abstract: A rate-independent constitutive model for natural clays is presented, formulated within the framework of kinematic hardening with elements of bounding surface plasticity. The modelling framework is intended to include effects of damage to structure caused by irrecoverable plastic strains caused by sampling, laboratory testing, or geotechnical loading. The incorporation of a structure measure allows the size of the bounding surface to decay with plastic deformations. This model can be seen as a logical extension from the Cam-clay model. The steady fall of stiffness with strain towards the Cam-clay value is controlled by a particular interpolation function. This ensures a smooth degree of approach between a kinematically hardening bubble (which is the boundary of the elastic region) and the bounding surface during their relative translation with stress history. The model describes the essential phenomena of pre-failure behaviour of natural clays: stiffness variation with strain, volumetric change accompanyi...