Failure analysis of gas turbine last stage bucket made of udimet 500 superalloy
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the stress increase from the loss of a load bearing cross-sectional area of the bucket tip shroud by the conversion of metal to the corrosion product (scale),
influence of the tip shroud microstructure (e.g., a presence of equiaxed and columnar grains, their distribution and orientation),
evidence of the transgranular initiation, and
intergranular creep mechanism propagation.
The most probable cause of the bucket damage was the combination of increased stresses due to corrosion-induced thinning of the tip shroud and unfavorable microstructures in the tip shroud region.
Keywordshot corrosion creep fatigue equiaxed grains columnar grains gas turbine buckets
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