Microstructure evolution and its effect on the impact toughness of the Ti-Al-V-Mo-Zr alloy tube
Guangfang Chi, Huiqun Liu
Abstract
Abstract Titanium alloys are widely used in the petrochemical industry owing to their excellent overall performance. In this study, a high-temperature solution treatment in the two-phase region was proposed, with a slow cooling rate resulting in the successful partial globularization of lamellar α microstructure, achieving an extruded Ti-Al-V-Mo-Zr alloy tube elongation increase of 69% and impact toughness increase of 51%. The kinking of lamellar α microstructure promoted its continuous globularization by increasing misorientation. Consequently, the elongation and impact toughness of Ti-Al-V-Mo-Zr alloy tubes could be greatly improved by tuning the microstructure to a mix of coarse equiaxed and lamellar α microstructures, the improved strength being attributed to the secondary α phase (α s ) obtained using the proposed method and aging. The results of this study can be expected to provide guidance for the fabrication of highly ductile titanium-alloy oil-drilling tubes. Graphical abstract