High Pressure Turbine Blade Life Extension.

摘要

The metallurgical basis for an extension of the service lifetime of directionally solidified Rene 80H HPT blades beyond the rated lifetime of 30,000 EFTC was studied. The study considered the effects of HIP processing and blade tip replacement via welding with MERL 72 on the microstructure of directionally-solidified Rene 80H (DS-R80H) superalloy blades. Elevated temperature tensile and creep rupture studies were conducted with DS-R80H specimens prepared from directionally solidified alloy test bars to ascertain the stress strain and strain time relationships and to evaluate microstructural characteristics at elevated temperatures under applied stresses. Included in the creep tests were DS-R80H specimens into which center sections of MERL 72 were inserted to evaluate the effects of stress at elevated temperature on the DS-R80H/MERL 72 interfacial integrity. In addition, the investigation considered the microstructure of MERL 72 re-tipped HPT blades following exposure of the blades in an ASMET (Accelerated Service Maintenance Engine Test) engine.