{10-12} Twinning Mechanism During <i>In Situ</i> Micro-Tensile Loading of Pure Mg: Role of Basal Slip and Twin-Twin Boundary Interaction

Evolution of Deformation Twinning Mechanisms in Magnesium from Low to High Strain Rates

“…Thus, once reaching the critical resolved shear stress for twinning (s T CRSS ), the overall energy of the system is reduced through energy dissipation. In displacement-controlled conditions the twin transformation process leads to a significant load drop in the r-e curves, as observed in our recent work [29]. Additionally, upon twin nucleation and under a continuously applied deformation condition, the predominance of the twin propagation process in accommodating the plastic deformation is usually manifested by a plateau of r, where a small increase in stress results in a signif- icant increase in strain [31,32].…”

“…3). This suggests that the formation of a twin nucleus of finite size occurs upon the activity of < a > dislocations underneath the pillar-indenter contact region, similar to what has been largely observed in Mg during direct and indirect c-axis extension at low strain rates [29,35,46]. The pillar tapering of $ 1-2°makes the top-back edge of the structures the principal twin initiation site (see Fig.…”

“…The BS of the {10 1 À 2} twin in Mg has been widely investigated as it contains the k 1 and g 1 directions of propagation, of high interest for understanding the motion of TDs on alternating K 1 planes. On the contrary, despite recent exceptions [29,[40][41][42][43][44], the DS still has not been sufficiently investigated experimentally as such projection is reported to be, in principle, ''crystallographically unobservable" [39]. Here, however, we assessed the spatial evolution of the twin grains of some deformed structures through a 3D EBSD reconstruction (Fig.…”

“…All EBSD maps were acquired inside a field emission gun (FEG) SEM (Tescan, Lyra3) with a Symmetry detector and Aztec 4.2 software (Oxford Instruments, UK), under 20 kV, 10nA beam conditions and a 100 nm step size, using a 2 Â 2 binning (622 Â 512 px 2 ). As EBSD is a surface technique, the three-dimensional reconstruction of the shape and distribution of the twins formed upon loading was performed by coupling post mortem 2D EBSD acquisitions with FIB tomography in a static setup [28,29] (see later). The 2D EBSD maps were captured after every FIB slice of 200 nm from the front surface through the thickness of the pillars.…”

Study on Microstructure and In Situ Tensile Deformation Behavior of Fe-25Mn-xAl-8Ni-C Alloy Prepared by Vacuum Arc Melting

“…This indicates that dislocations in austenite grains begin to slip. According to the relevant data, it is determined to be basal slip [27,28]. When the strain increases to 4.0%, the stress increases to 626.2 MPa.…”