Spall strength of titanium alloys

• Published in: Physical mesomechanics Vol. 13; no. 3; pp. 113 - 123
• Main Authors: Divakov, A.K., Mescheryakov, Yu.I., Zhigacheva, N.I., Barakhtin, B.K., Gooch, W.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2010
• Subjects: microstructure; phase transition; shock loading; spall strength; Titanium alloys; Titanium alloys; spall strength; microstructure; phase transition; shock loading
• ISSN: 1029-9599; 1990-5424
• DOI: 10.1016/j.physme.2010.07.002

A series of high-velocity impact tests of impactors and targets of varying acoustic impedance, including Al – Ti, steel – Ti and Ti – Ti combinations, reveals a β↔ω to phase transition in α + β Ti alloys under shock loading. The presence of the to-phase is confirmed by X-ray diffraction analysis of Ti-4.5Al-3Mo- IV alloy specimens loaded with an impactor at different impact velocities. The experiments show that at an impact velocity greater than ∼ 500 m/s, spall fracture occurs earlier than the ω→ x reverse transition (where x is the α-phase, or the β-phase, or their mixture) takes place during the decay of the compression pulse. Hence, the spall fracture in the material develops in the presence of the ω-phase whose dynamic strength is much smaller than that of the β-phase. For the spall occurring after the to ω→ x reverse transition, the spall strength of the alloy increases by 25%.