Process for strengthening the grain boundaries of a component made from a Ni based superalloy
AssigneeAlstom (Switzerland) Ltd
InventorJohn Fernihough
Life of this patent
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Abstract
The invention relates to a process for the forming of precipitates of carbides and borides along the grain boundaries of an component made from an Ni based superalloy while in solid state. This follows from the finding that the carbides formed by carburization offer similar grain boundary strengthening properties as those cast into the article using the current art without the detrimental effects of adding more carbon to the alloy prior to casting. With advantage the process will be carried out in a way to form secondary caribides in the form Cr23C6, Cr7C, Cr6C and HfC and may take place before, during or after the normal solution and/or precipitation hardening heat treatments of the component.
Claims17
A process for strengthening grain boundaries of a cast component made from a single crystal or columnar grain type Ni based superalloy, the process comprising:
- applying a solid, liquid or gas containing at least one of carbon or boron to a surface of the component said surface containing at least one grain boundary found within the component;
- allowing sufficient time for the at least one of carbon or boron to diffuse into the at least one grain boundary of the component;
- and
- forming precipitates comprising at least one of carbides or borides on the grain boundaries throughout the component while the component is in the solid state.
Dependencies are inferred from the claim text.