Grain size and void formation in Mg alloy AZ31

A rationale for the influence of grain size on failure of magnesium alloy AZ31: An in situ X-ray microtomography study

“…In the fine-grained material, however, most of the voids (70%) nucleated at second-phase particles (type I). This suggests that the mechanism of void nucleation is sensitive to the grain size and agrees with previous findings [49]. However, there is no correlation between the void size (i.e.…”

“…It is not completely clear how this rationale should be applied to understand the strong beneficial impact of grain refinement on the tensile ductility of magnesium. In addition to the influence of grain size on deformation mode activity noted above, we have recently seen that in alloy AZ31 [49] the grain size seems to impact on void size and also that void nucleation at second-phase particles is more prevalent for finer grain sizes. These findings were limited to void information gathered at the point of fracture and the present study was initiated to validate the findings using strain mapping, interrupted x-ray tomography and void characterization.…”

“…The as-received material was a 150mm-thick, commercial hot-rolled AZ31 alloy with an average grain size of 30 μm and a chemical composition (wt%) of 3.12Al-1.3Zn-0.36Mn (Mg the balance) [49].…”

A crystal plasticity investigation of grain size-texture interaction in magnesium alloys

“…In fine-grained microstructures, a reduced propensity to twinning has been posited to decelerate void growth, although in the process it may activate an alternate failure mode, e.g. shear instability [10,11]. Nevertheless, others report improved tensile ductility in the presence rather than the absence of extension twinning in fine-grained Mg alloys [31].…”

“…Several conventional as well as novel strategies are investigated to engineer Mg microstructures with enhanced yield strength and strain hardening. These include: grain size refinement [6][7][8][9][10][11], alloy engineering for solute [12][13][14] and precipitate [12,15,16] strengthening, nanostructured [17,18], hierarchical composites [19], texture modification [8], and combinations thereof.…”