Impact response of pre-strained pure vanadium

The effect of modest, 0.6% and 5.5%, pre-straining on the impact response 2 mm thick samples annealed polycrystalline vanadium commercial purity was studied in a series planar tests. loading by 0.5 copper impactors having velocities varying between 300 610 m/s accompanied continuous laser Doppler velocimetry their rear surface. Based recorded velocity histories, dynamic compressive [Formula: see text] tensile (spall) strengths strength shock-compressed state were determined. Adjacent to surface part cross sections softly recovered samples, number twins per unit area counted. It found that main parameter governing both pristine (in shock sense) material state, text], initial dislocation density text]. Moreover, surplus caused responsible for complete suppressing twinning 5.5% pre-strained samples. In undeformed vanadium, partially suppressed presence impurity atoms which, however, did not affect stress, which equal approximately 0.7 GPa.