Edge Effects at Spall Fracture for Titanium Alloys of Varying Oxygen Content.
Final rept. 18 Sep 97-1 Jul 98
ARMY RESEARCH DEVELOPMENT AND STANDARDIZATION GROUP (UNITED KINGDOM) FPO NEWYORK 09510
Pagination or Media Count:
The samples of as-received Ti-6A1-4V alloys of 3 different oxygen contents ranging from 0.1 to 0.24 have been tested in about 50 shock-wave experiments. In the experiments performed the Hugoniot elastic limit, the spall strength, and the critical diameter for the spall element separation were measured. The peak shock stress was varied from 4 to 75 GPa, the load duration from 10exp -7 s to 10exp -5 s. The VISAR free-surface velocity measurements show a growth by 20 in the Hugoniot elastic limit of alloys with increasing the oxygen content from 0.105 up to 0.24. The measurements have not revealed a notable variations in the spall strength magnitudes as a function of the oxygen content. The spall strength grows by 10 to 20 when the load duration decreases by an order of magnitude. The peak stress in shock wave preceding to spall fracture does not influence the spall strength value. The computer simulation of spall experiments was performed with the 1-D Lagrangian code. The description of the elastic-plastic properties is based on the structural Marzing model. Fracture was calculated using the empirical constitutive relationship which provides quite reasonable description of the spall process.
- Properties of Metals and Alloys