The prediction method of remnant life of creep fracture coupled with QL^* parameter and micro erosion method for notched specimens of Ni-base super alloys

Abstract

Turbine blades and disks in which Ni-base super alloys are used are subjected to severe operating conditions, which result in creep deformation due to centrifugal force and notch effects induced by cooling holes and blade attachment parts. Therefore, establishment of a nondestructive prediction method for the remnant life of creep fracture life is essential to conduct suitable maintenance of turbine blades and disks. The relationship between the QL* parameter and micro grinding resistance measured by MSE (Micro Slurry-jet Erosion) was investigated to establish a prediction method of creep remnant life for Ni-base super alloys. Comparing the QL* parameter and results of MSE of interrupted specimens for polycrystalline and single-crystal Ni-base super alloys, it was found to exist a universal relationship between the stage of aging degradation and micro grinding resistance of these materials, and the validity of using the MSE test for predicting creep remnant life was confirmed.

Keywords:

• Creep
• remnant life
• QL^*
• MSE
• Ni base super alloys

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Corrigendum

Acknowledgement

This article is based on results obtained from a future pioneering program commissioned by the New Energy and Industrial Development Organization (NEDO).