Impact resistance of NiAl alloys

Ballistic impact tests were conducted on NiAl alloys using conditions simulative of those in the turbine section of aircraft engines. Several parameters including velocity, impacting particle mass and thickness, target thickness and impact angle were varied in tests conducted at approximately 980°C. Impact damage of the single crystal NiAl alloy typically occurred due to high bending stresses on the backside of the impact panel resulting in complete failure of the specimen. Impact angle and target thickness were found to be important in determining the impact resistance of the specimens. It was found that single crystal NiAl alloys do not survive most impact conditions simulative of turbine blades, but demonstrated feasibility under impact conditions simulative of turbine vanes. The single crystal NiAl alloy results were similar to silicon nitride results reported in the literature, while a NiAl eutectic alloy evaluated in this study performed slightly better than both of these materials.