Effect of Aluminum and Grain Size on the Fracture Behavior of Twinning-Induced Plasticity Steels

Revealing effect of aluminum alloying on work hardening and impact behaviors of low-density Fe-18Mn-1.3C-2Cr-(4, 11)Al casting steel

“…After the high speed plastic deformation, the cleavages were observed on both two kinds of steels, accompanied by a drop in ductility and toughness. Luo and Huang [17] and Koyama et al [33] found that the twin boundaries with dislocation pile-ups, twin intersection points, and junctions between twin and grain boundary were the possible cleavage formation sites. Furthermore, Milititsky et al [34] and Tomota et al [35] argued that the strong planarity of HDDWs piling up on {111} planes brought considerable high stress concentration, and finally cleavage facets formed.…”

“…This reversing trend, with Al addition, is attributed to the presence of ferrite, leading to poor plasticity with Al content up to 10wt.%. Luo and Huang [17] pointed out that the twin-twin and/or dislocation pileups-twin intersections, in coarse-grained Fe-18Mn-0.75C-1.7Al-0.5Si (wt.%) steel, plays an important role in promoting localized microcracks nucleation and cleavage fractures formation. In general, it thus appears that the ferrite phase, twin-twin intersection, and dislocation pileups-twin intersection determine the ductility and fracture behavior of low-density steel.…”