Research on Growth of Microcracks in Nickel-Base Superalloys.

摘要

The growth of very small, 0.06-0.15 mm, fatigue cracks in a powder metallurgy nickel-base superalloy, IN-100, was studied. Tests were conducted at room temperature and at 650 C. The crack growth rates were measured by means of a 600X microscope which allowed in situ crack length measurement, even at elevated temperature. The interaction of the crack and the material microstructure was observed in a fatigue loading stage which operated in the Scanning Electron Microscope. A technique for experimentally determining stress intensity factors was also developed.