Structural heat-resistant β-NiAl + γ′-Ni3Al alloys of the Ni–Al–Co system: II. Oxidation

Abstract

The heat resistance of the β + γ′ alloys with 28–29 at % Al, 10 at % Co, and 0.25–0.4 at % Re in air at 1300°C is studied. The structures of the scale and the subscale layers that form during oxidation for 2 and 100 h due to the interdiffusion of aluminum and oxygen are investigated. Alloying with 10 at % Co is shown to increase the heat resistance in the absence of chromium and a low content of the elements tht are active to oxygen (La). The heat resistance of the β + γ′ NIAL1 and NIAL2 alloys at 1300°C, which was estimated from the surface unit mass increment in 100 h, is at level of the heat resistance of the γ′ + γ VKNA (VIN) alloys at 1200–1250°C.