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MM: Fachverband Metall- und Materialphysik

MM 36: Topical Session: Advanced Nanomechanics – Accelerating Materials Physics from the Bottom II

MM 36.5: Vortrag

Donnerstag, 12. März 2026, 17:00–17:15, SCH/A251

Experimental evidence and first-principles verification of deformation of basal twist grain boundaries in Ti — •Biaobiao Yang^1,2, Samuel Hémery³, Wei Shao^1,2, Victoria Tucker^1,4, Michael S. Titus^1,4, Miguel A. Monclús¹, and Javier LLorca^1,2 — ¹IMDEA Materials Institute, C/Eric Kandel 2, Getafe, 28906 - Madrid, Spain — ²Department of Materials Science, Polytechnic University of Madrid / Universidad Politécnica de Madrid, E.T.S. de Ingenieros de Caminos, 28040 - Madrid, Spain — ³Institut Pprime, ISAE-ENSMA, Université de Poitiers, CNRS UPR 3346, Téléport 2, 1 avenue Clément Ader, BP 40109, Futuroscope-Chasseneuil Cedex, 86961, France — ⁴School of Materials Engineering, Purdue University, 701 West Stadium Ave., West Lafayette, IN 47907, USA

Recent studies show that Basal Twist Grain Boundaries (BTGBs) are important fatigue-crack nucleation sites in Ti alloys. Micropillar compression combined with high-resolution microscopy revealed extremely easy interfacial shear: one basal grain slides over the other at very low critical resolved shear stresses (45-205 MPa), far below those required for common <a> basal slip. To explain this behavior, first-principles calculations were used to determine the grain boundary energies of BTGBs with different twist angles. The results show that variations in twist angle or in-plane translation produce only negligible changes in grain boundary energy, indicating intrinsically low shear resistance. Together, these experimental and computational findings clarify why BTGBs serve as potent crack-nucleation sites in Ti alloys.

Keywords: Titanium; Basal twist grain boundary; Micropillar compression; First-principles calculation