Hot isostatic pressing of a high temperature Ni-superalloy CM247LC: processing-microstructure-properties

MacDonald, James Edward (2017). Hot isostatic pressing of a high temperature Ni-superalloy CM247LC: processing-microstructure-properties. University of Birmingham. Ph.D.

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Abstract

Hot isostatic pressing (HIP) is of interest to the aerospace industry due to the ability to produce polycrystalline components free from defects, which typically exhibit comparable or superior properties to their cast counterparts. The capability also exists with powder HIP to produce large parts with complex designs to near netshape (NNSHIP) in a single processing step, which can potentially reduce the buy-to-fly ratio ofhigh temperature gas turbine engine components. Such components, however, are manufactured from Ni-superalloys and certain issues exist with the HIP ofNi-superalloys that require addressing.
The research presented in this thesis investigates HIP of a Ni-superalloy CM247LC to assess the viability of the process and the alloy for high temperature turbine and combustor casing components of the future. The influence of powder characteristics, post-HIP heat treatment and modification of the HIP procedure, have been investigated to assess the effects on high temperature properties. HIPped CM247LC can significantly outperform cast CM247LC in terms of hot tensile properties (particularly ductility), suggesting NNSHIP is potentially viable. In the current work, however, poor creep resistance was exhibited which is a concern for high temperature components.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):