Crystal orientation dependence of crack growth and crack-tip deformation in iron–3 wt.% Si single-crystal thin plates = Sự phụ thuộc của hướng tinh thể đối với sự phát triển vết nứt và biến dạng tại đầu vết nứt trong các tấm mỏng đơn tinh thể iron–3 wt.% Si

Abstract

This paper investigates the influence of crystallographic crack orientation on crack growth and crack-tip deformation in Fe-3 wt.% Si single-crystal thin plates. Two crack orientations, (101) [010] and (010) [101], are examined through displacement-controlled uniaxial tensile tests at room temperature. Crack propagation is continuously monitored using optical microscopy, while post-test surface morphology and slip activity are analyzed by scanning electron microscopy. Stable ductile crack growth occurs in both orientations, but significant differences are observed in crack-growth rate and crack-tip deformation. The (101) [010] orientation exhibits substantially larger crack-tip opening angles, extensive slip activity, and pronounced crack-tip blunting, whereas the (010) [101] orientation shows smaller opening angles and faster crack propagation. These differences are attributed to orientation-dependent slip activation and interactions between in-plane and out-of-plane deformation near the crack tip. The results demonstrate that crystallographic orientation strongly governs crack-growth mechanisms by controlling local plastic deformation and dislocation behavior, providing fundamental insights for texture-controlled design of Fe–Si alloys with improved crack resistance.