Correlation between Microstructures and Properties of TC21 Titanium Alloy Φ350mm Bars

This paper studied the correlation between the properties and three microstructures of equal-axial, basket and widmanstatten of TC21 Phi. 350mm bars. The results show that, there is no much difference of the strength among the three kinds of microstructures. The ductility of equal-axial structure is the highest, ductility of widmanstatten structure is the lowest, and the ductility of basket structure is in between when the corresponding room temperature tensile strength is in the range of 1090-1095MPa and the elongation is from 7. 5% to 10. 5%. There is no much difference among the three kinds of microstructures and the ductility is from 9. 5%) to 13% which progressively decreases according to equal-axial, basket to widmanstatten structure when the high temperature strength is in the range of 820-824MPa at 400 degrees C; The KIC of the basket and widmanstatten structure is higher, i.e. >= 70MPam(1/2), the KIC of equal-axial structure is lower, i.e. >= 50MPam(1/2). The high strength and high toughness TC21 material is suitable to be used in the key support structure of aircraft, and has a flourishing developing future.