Microstructures and high temperature properties of Ni{sub}3Al with B and/or Hf.

摘要

An intermetallic compound, Ni{sub}3Al shows an unusual property that strength increases with higher temperature in the range below 900℃.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 ofγ 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℃ and hot workability.