Abstract: A nanolayered coating, having a thickness of less than 100 nm, comprising nanolayers of: (i) TiN; and (ii) CrN, MoN, AlN, or AlN and CrN. The coating has an erosion rate, according to ASTM G76, at a particle velocity of 60 m/s and an impingement angle of 90°, of no greater than 4.0×10?3 mm3/g. Also provided is a monolithic TiAlN coating. Such coatings may be useful for erosion protection of aircraft or gas turbine components; or wear protection of gears, cutting tools including machine cutting tools and surgical cutting tools, or other metallic surfaces.

Abstract: A method for producing fine-grained lamellar microstructures in powder metallurgy (P/M) and wrought gamma titanium aluminides comprises the steps of: (a) a cyclic heat treatment at a maximum temperature in the range of about 10.degree. C. above to about 10.degree. C. below the alpha-transus temperature (T.sub..alpha.) of the alloy, and (b) a secondary heat treatment of thus cyclically heat treated alloy at a temperature between 750.degree. C. and 1050.degree. C. for 4 to 100 hours. For cast gamma alloys, the method comprises additionally the step of a solution treatment at a temperature in the range of about 30.degree. C. to 70.degree. C. above T.sub..alpha. followed by a water or an oil quench before the two steps described above. The alloys with the resulting fine-grained lamellar microstructure have an advantageous combination of mechanical properties--tensile strength, ductility, fracture toughness, and creep resistance.