Ballistic Evaluation, Part Ⅱ: Austempered Malleable and Austempered Ductile Irons

摘要

1. Austempered ductile 600 iron is the most effective armor material of the three materials investigated in this program. It has the highest value of E_*, and it provides more protection against a long rod penetrator than either the ductile 650 or the malleable 600 materials. 2. E_* for the ductile 600 iron is approximately 5% higher than that for rolled homogeneous armor steel—214 Btu/lbm, compared to 203 Btu/lbm, 3. Austempered ductile 600 iron requires 11% less weight and approximately the same thickness as hardened, wrought 4340 steel to defeat a typical long rod kinetic energy penetrator. 4. Austempered iron materials exhibit brittle failure to varying degrees and significant rear surface spall. Of the three materials tested, the most brittle is the malleable 600, while the least brittle is the ductile 650. 5. Austempered ductile 600 iron could be an effective armor material if used in conjunction with ductile materials that alleviate the effects of spall debris.