This is the base of a turbine airfoil of the J58 engine. The remaining portion appears to have been sheared off upon impact. The material is likely a nickel-based superalloy. Reference images below for comparison.
Prior to the SR-71, jet engine turbines were cast using methods that could lead to minor imperfections due to the polycrystalline structure of the metal. These imperfections were tolerated at the time, but as engine became more powerful and ran at higher temperatures, these imperfections had to be addressed.
The construction of the SR-71 paved the way in the development of single-crystalline superalloy airfoils. Over 200 scientists and engineers worked over 10 years to perfect this technology that is now used throughout the aviation industry.
Size: 1" x 1.25" x 2.25"
The sale price includes the item(s) pictured, verified provenance, & certificate of authenticity.