Nickel base superalloy single crystal articles with improved performance in air and hydrogen

摘要

Compositional requirements and processing improvements are disclosed which improve the hydrogen embrittlement resistance and the fatigue resistance in air of nickel base single crystal articles. The compositional requirements enlarge the difference between the gamma' solvus temperature and the incipient melting temperature, thus enabling the solution of gamma/gamma' eutectic islands without causing incipient melting, while hot isostatic pressing and careful melt practice eliminate porosity and carbides, borides and nitrides, all of which act as crack initiation sites.