Evaluation of Elastomers, Plastics, Coatings and Metals

This report is divided into two sections, one covering the mechanical properties of metals and the other the evaluation of nonmetallic materials. The first section studies the fracture and crack growth properties of the primary structural materials, HP 9Ni-4C0-20C steel, 2024-T851 aluminum, and Ti-6Al-4V titanium for the B-1. Other system support programs included the evaluation of landing gears fabricated from 7175-T736 and 7049-T73 and special tensile and elongation measurements of bolts. Also described are a computer program for analyzing crack growth data and studies of fatigue crack growth retardation and fatigue crack starter defects. The second section describes the evaluation of nonmetallic materials, principally elastomers, fuel tank sealants, fuel cell coatings and the mechanical property, compatibility, and hydrolytic stability testing of exterior fuel cell foams and coatings. (Modified author abstract)