Spalling strength and phase transitions in titanium alloys under impact loading

Spalling strength of four types of high-strength titanium alloys, VT-6S, VT 3-1, VT-16, and VT-20 was measured. After shock loading abnormal rotational helical structures 10-20 mu m in size were observed in the spallation zone . VT-16 alloy was found to exhibit the highest spalling strength. The densi ty of helical structures in this alloy was the highest. Forward and backwar d alpha-omega phase transitions were revealed in all the alloys studied. Th e thresholds of these transitions rise monotonically as the strain rate inc reases.