Activation of contraction twins during compression and related texture characteristics in α-titanium

• Published in: Materials characterization Vol. 214; p. 114123
• Main Authors: Chouhan, Devesh Kumar, Tóth, Laszlo S., Biswas, Somjeet
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2024
• Subjects: Coincident site lattice; Contraction twins; Extension twins; Schmid law, texture; Titanium; Titanium; Contraction twins; Extension twins; Coincident site lattice; Schmid law, texture
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2024.114123

This work demonstrates that axial compression along 0002and101¯0 in individual grains of α-Titanium can effectively activate up to six variants of 112¯2112¯3¯ contraction twins (CT). Compression parallel to 101¯0 primarily introduces 101¯2101¯1¯ type extension twins (ET), orienting the c-axis almost along the compression axis. Further compression activates up to six 112¯2112¯3¯ CT variants, each with a specific orientation having Euler angles of (0°−60°+n60°, 63.5°, 30°), where n is the sequence number of the CT variant. All six CT variants may not be activated during uniaxial compression due to the deviation of the parent grains' c-axis from the compression direction (CD) and deformation heterogeneities. The nucleation and interaction of CT variants lead to the formation of coincident site lattice boundaries with characteristics (θ−uvtw) angle axis pair of 63.5°101¯0−∑7b, 51.2°11¯00−∑23a, 60°112¯1−∑19b, and 77.3°18¯70−∑17b. The activation of multi CT variants and their interaction can contribute to grain fragmentation and texture weakening. From statistical analyses, the nucleation and growth of CT variants appeared to follow the Schmid law. However, deviations from the Schmid behavior occurred by the activation of low Schmid factor CT variants and could be attributed to slip and twin activities in neighbor grains. [Display omitted] •Experimental observation of multiple 112¯2112¯3¯ contraction twin (CT) variants in individual grains of α-Ti by compression.•CT variants' texture forms in φ2=30° section of orientation space at ∼60° intervals along φ1 and at φ=63.5°.•Multiple CT variants interact to form ∑7a,∑17b, ∑19b and ∑23a CSL boundaries.•CT evolution usually follows the SF criteria.•Slip/twin-assisted lattice curvature near grain boundaries could increase local SF to activate low global SF CT variants.•Euler angle plots can distinguish CT variants better than inverse pole figure maps.