Deformation Asymmetry of AZ31 Wrought Magnesium Alloy

Abstract

In this work, the mechanical behaviour of an AZ31 wrought magnesium alloy due to tensile, compressive and four-point bending tests was analysed. Several specimens of this material were taken in different directions from a rolled plate. Tensile and compression tests allowed to characterise the mechanical properties of the material in the rolling and cross rolling directions. To take the effect of the anisotropy induced by the rolling procedure itself into account, the bending tests were carried out using specimens with four different orientations. Six strain gages per specimen allowed to observe the evolution of the strain with the bending moment during the tests. All bending specimens were bent until a total compressive deformation of 2.5%. It was observed that the corresponding tensile strain was significant lower and slightly different for each orientation of the specimens. In addition, a characteristic non-uniform distribution of deformation twinning was observed. The induced residual stresses after bending were characterised by X-ray diffraction (XRD) and incremental hole-drilling (IHD). Due to the different mechanical behaviour in tension and compression, an asymmetric residual stress distribution after bending could be observed. The neutral axis was, in all cases, shifted towards the tensile side. This observation agrees with the strain measurements during bending tests. In addition, an example of the influence of the asymmetric deformation behaviour during fatigue was given.

Strain-Controlled Low-Cycle Fatigue Properties of a Newly Developed Extruded Magnesium Alloy

“…This is attributed to the tensile and compressive yield asymmetry observed in wrought magnesium alloys. [33] Plots of mean stress vs the number of cycles for each strain ratio are shown in Figure 16. It is evident that at the lower strain ratio smaller mean stress evolved and the mean stress increased until 600 cycles, which was close to the half-life cycle.…”

Silicon Carbide Dispersion Strengthening of Magnesium Using Mechanical Alloying Method

“…Nobre et al 8) have reported that bending strength values of 200-220 MPa were obtained for a compressive strain of 2.5% using the 4-point bending test on AZ31 wrought magnesium alloys (length of 160 mm, width of 15 or 20 mm, and thickness of 10 mm).…”

An elasto-plastic constitutive model for evolving asymmetric/anisotropic hardening behavior of AZ31B and ZEK100 magnesium alloy sheets considering monotonic and reverse loading paths

“…al., 2007;Knezevic et al, 2010). The compressive hardening behavior of Mg sheet is characterized by an S-shaped sigmoidal hardening curve exhibiting a low initial yield stress (Nobre et al, 2002) followed by a concave-up stress-strain behavior with a low initial hardening rate due to extension twinning (Yukutake et al, 2003). At large compressive strain, due to the exhaustion of twinning and M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 dominance of slip mechanisms, the stress strain curve switches to that of a typical concave-down shape (Yukutake et al, 2003;Lou et.…”