Abstract
An intermetallic compound, Ni3Al shows an unusual property that strength increases with higher temperature in the range below 900°C.
Accordingly, it seems to be applicable to turbine blades for jet engines. However, it is well known that the hot workability is markedly inferior.
From these viewpoints, the effects of a small amount of B and Hf on hot workability, microstructures, and high temperature strengths were investigated.
The specimens used in this experiment contained about 11% Al and indicated duplex structures of γ and nearly 30% γ′. Therefore, they showed on reverse dependence on temperature with regard to high temperature strength.
Adequately added B and Hf to the specimens improved creep rupture strength at 750 and 800°C and hot workability.
