Three-dimensional lamellar orientation and stress condition induced sudden fracture of directional solidified γ-TiAl alloys produced by electromagnetic confinement

Abstract

Ф 16.5 mm directional solidified Ti-45Al-5Nb alloys with full-lamellar microstructure were successfully obtained through electromagnetic confinement and seed crystal methods. Tensile experiments at ambient temperature were performed to evaluate the industrial processability of the alloy. Although the angle between the full-lamellar structure and the applied stress is approximately 0°, the elongation is still extremely low. The fracture morphology and internal microstructure were observed from multiple directions. Combined with external mechanical stress condition, the reason for sudden fracture was discovered and the lamella orientation control plan is proposed based on different specimen conditions. The cognition of the relationship between the lamellar orientation and mechanical performance was supplemented and expanded on the three-dimensional scale.