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A robust understanding of the deformation behaviour of magnesium alloys under complex loading paths is a prerequisite to the successful fabrication of parts and understanding of their in- service performance. To facilitate this, multi-axial testing has been conducted on thin walled cylindrical samples of cast AZ80 alloy possessing weak initial texture. Internal pressurization, controlled by closed-loop feedback system permits hoop stresses to be created within the sample wall. When generated in conjunction with axial loading this allows a range of biaxial tensile loadings to be induced within the tension-tension quadrant of stress space. In order to facilitate an understanding of the textural evolution of weakly textured AZ80 subjected to these loadings, texture measurements have been conducted on as tested samples via neutron diffraction. This work builds off of prior work which has characterized the behaviour of AZ80 in uniaxial tension and compression and integrates these results. These mechanical testing results have been compared to those predicted by crystal plasticity simulations in order to help understand the deformation behaviour well as texture evolution., Mg2012: 9th International Conference on Magnesium Alloys and their Applications, 8-12 July 2012, Vancouver, Canada

In-situ neutron diffraction has been used to measure lattice strains for different grain orientations as a function of applied stress in a solid-solution-strengthened extruded binary Mg-9wt.%Al alloy. An elastic-viscoplastic self-consistent (EVPSC) model of polycrystal plasticity was used to simulate the macroscopic stress-strain curve and the neutron diffraction data, yielding the relative contributions, critical resolved shear stresses and hardening behavior of the available slip and twinning modes. Non-linear behavior was observed during unloading after deforming the material into the fully plastic regime in tension. The model suggests that this non-linear behavior is mainly due to basal slip., Mg2012: 9th International Conference on Magnesium Alloys and their Applications, 8-12 July 2012, Vancouver, Canada

A constitutive materials model, which includes Ohno-Wang's kinematic hardening rule, is employed to simulate the isothermal monotonic and cyclic behaviours of high-pressure die cast magnesium AM60B alloy under uniaxial loading condition. An implicit constitutive stress integration scheme developed by Kobayashi and Ohno [Int. J. Numer. Methods Eng. (2002) 2217] is used to code the model into an ABAQUS user materials subroutine (UMAT). After the material parameters used in the current model were obtained from the experimental results, the predictive capability of the model was verified. © 2008 Blackwell Publishing Ltd.

In-situ neutron diffraction has been employed to study the deformation mechanisms in a precipitation-hardened and extruded Mg-8.5wt.% Al alloy subjected to compression followed by reverse tension. The starting texture is such that the basal poles of most grains are oriented normal to the extrusion axis and a small portion of grains are oriented with the basal pole parallel to the extrusion axis. Diffraction peak intensities for several grain orientations monitored in-situ during deformation show that deformation twinning plays an important role in the elastic-plastic transition and subsequent plastic deformation behavior. Significant non-linear behavior is observed during unloading after compression and appears to be due to detwinning. This effect is much stronger after compressive loading than after tensile loading., Magnesium Technology 2011 - TMS 2011 Annual Meeting and Exhibition, 27 February 2011 through 3 March 2011, San Diego, CA

The mechanical behaviours of a high-pressure die cast AM60B magnesium alloy were studied. Monotonic and cyclic tests (with a strain ratio R = -1) were carried out at ambient temperature. The results of the mechanical testing were discussed with respect to the crystallographic texture and the microstructure of the alloy in terms of clusters of pores, grain size, second phase strengthening as well as the orientation-dependent activation of different deformation mechanisms such as slip and twinning. © 2008 Blackwell Publishing Ltd.