Accession Number : ADA267124


Title :   Turbine Blade Refurbishment


Descriptive Note : Final rept.,


Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC


Personal Author(s) : Smith, Hugh H ; Michel, David J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a267124.pdf


Report Date : 12 Jul 1993


Pagination or Media Count : 18


Abstract : An investigation of metallurgical improvements and repair procedures to extend the service life to F404 high pressure turbine blades has been conducted. The first phase of the investigation was directed towards the evaluation of directionally solidified Rene'80H superalloy specimens and blades and has been previously published. In the study reported herein, the elevated temperature creep-rupture properties of single crystal Rene'N4 specimens were determined and compared to the creep properties of the directionally solidified Rene'80H specimens. For the range of stresses and temperatures investigated, the creep-rupture life of single crystal specimens was at least twice that of the directionally solidified specimens. In addition, it was proposed to extend the life of turbine blades by refurbishment of damaged blade tips with MERL 72 weld overlays. The creep-rupture behavior and interfacial integrity of composite Rene'N4/ MERL 72 specimens was found to be satisfactory and comparable to composite Rene'80H/MERL 72 specimens. Comparisons of creep performance of single weld specimens (to simulate a tip repair) and re-weld specimens (to simulate a second tip repair) showed that the creep life of re-welded specimens was reduced compared to the single weld condition. The creep results and metallographic observations of the creep failure processes are presented and discussed.... Nickel-base superalloys, Microstructures, Creep-rupture, Elevated temperatures, Strength, Mechanical properties.


Descriptors :   *TURBINE BLADES , *SUPERALLOYS , *METALLURGY , STRESSES , TEMPERATURE , MECHANICAL PROPERTIES , MICROSTRUCTURE , LIFE EXPECTANCY(SERVICE LIFE) , COMPARISON , REPAIR , CREEP , BLADE TIPS , OVERLAYS , FAILURE(MECHANICS) , BEHAVIOR , NICKEL , PRESSURE , SINGLE CRYSTALS , HIGH PRESSURE , STRAIN(MECHANICS) , RUPTURE , STRENGTH(MECHANICS) , WELDS


Subject Categories : Metallurgy and Metallography
      Properties of Metals and Alloys
      Hydraulic and Pneumatic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE