Nucleation of paired twins at grain boundaries in titanium

Study of $$ \{ 11\bar{2} 1\} $$ Twinning in α-Ti by EBSD and Laue Microdiffraction

“…At the intersection of a T2 twin and a grain boundary, a T1 twin is often observed on the other side of the grain boundary (will be referred to as ''T2 + T1 twin pair'' following [56] ). For example, the pink T2 twin in Grain 1 stimulated T1 twins in the adjacent grains from both its upper end and its lower end (see circles in the EBSD maps in Figures 2(b) and (c)).…”

Co-zone {1¯012} Twin Interaction in Magnesium Single Crystal

“…[2][3][4][5][6] Twinning and de-twinning are recognized to play crucial roles in developing the asymmetric stress-strain hysteresis loop, texture evolution, and initiation of fracture. [3,5,7] In properly oriented single crystals, multiple twins can be activated and interact with each other. As a consequence, their interaction and reactions develop a characteristic locked 'quilted looking' twinning structure (Figure 1(a)) which affects subsequent twinning and de-twinning, causes twinning-induced hardening, and potentially results in crack initiation.…”

“…As a consequence, their interaction and reactions develop a characteristic locked 'quilted looking' twinning structure (Figure 1(a)) which affects subsequent twinning and de-twinning, causes twinning-induced hardening, and potentially results in crack initiation. [3][4][5][6][7] Jiang et al [8] and Yang and Zhang [9] reported that different twin variants and twin-twin intersections are associated with the deformation stage with a higher strain hardening rate in AZ31 Mg alloy which is subjected to compression along the extrusion direction. Ma et al [10] and Oppedal et al [11] found that multivariants are activated to accommodate large straining and the subsequent twin-twin interaction contributes to a significant strain hardening.…”

Proceedings of the 13th World Conference on Titanium

“…In contrast, a similarly sophisticated analyses of the transfer coefficient for {10-12}<-1011> tensile twinning did not display a difference of values computed from within twin chains/clusters compared to calculating the transfer coefficient distribution of the related twinfree grain family and their neighbourhood, Figure 7b. This is interesting as one might argue that a shift towards higher m'-values within twin clusters/chains would have emphasised the importance of twins nucleating twins in neighbouring grains by creating stress concentrations, as observed in [14]{Barnett 2012}-. As this concept should be most effective when the shear strain of the twinned grain is of similar direction of the twin shear strain induced in the neighbouring grain, i.e.…”

“…The slip activity in a grain well aligned for prismatic <a> slip leading to twin nucleation in a neighbouring grain not well aligned for <a> type slip was shown to be significant when a tensile stress state was created [13]. Twin to twin shear transfer across grain boundaries has also been observed, particularly in boundaries with misorientations lower than 30° [14]. These correlations were quantified using the slip transfer parameter m', which was first introduced by Luster and Morris [15].…”