Ballistic impact performance of metals for high temperature jet engine fan containment applications

摘要

Ballistic impact tests were conducted at room temperature and at 370°C on five selected metals to determine their suitability for use in high temperature jet engine fan containment systems. The materials tested were M152 steel, Titanium 6242, Timetal 21S, Inconel 718 (in two heat-treated conditions) and Aermet 100 high strength steel. The impact tests were conducted on 35cm square flat panels clamped on all sides over a fixture with a 30.5cm×30.5cm square aperture. Projectiles were 25.4 mm long, 12.7 mm diameter flat faced Ti-6Al-4V cylinders with a 0.8 mm radius on the edge of the impacting face. Tests were conducted on two thicknesses of each material with impact velocities in the range of 100 - 400 m/sec. Room temperature quasistatic tensile tests were also conducted on specimens machined from the plate material. The ballistic limit (velocity required to just penetrate the specimen) was determined for each material. In general the more ductile materials performed better under the conditions studied, and there was a strong correlation between the ballistic limit and both the static strain to failure and the static toughness. The strength and hardness of the materials did not correlate with ballistic limit. Inconel 718 in the annealed state showed the greatest resistance to the impact damage under the conditions tested.