Comportamiento a fatiga de baja frecuencia del compuesto Rene®80 recubierto de aluminuro de platino cerca y por encima del DBTT

Abstract

Ni-based superalloy Rene®80 is used for manufacturing gas turbine blades in jet engines. The lifetime of some jet engine turbine blades is limited by low cycle fatigue and this property has been strongly affected by coatings. Ductile to Brittle Transition Temperature (DBTT) is the most important factor which affects the mechanical properties of coated alloys. In this study, high temperature-low cycle fatigue behavior of uncoated and coated Rene®80 by platinum-aluminide (Pt-Al) was evaluated at temperatures 871 °C (near the DBTT) and 982 °C (above the DBTT). Results of low cycle fatigue tests under strain-controlled condition at 871 °C for R =0 and strain rate of 2×10-3 s-1, at a total strain range of 0.8% showed a decrease in fatigue strength of coated specimens about 14%, compared to the uncoated ones. However, increasing the testing temperature from 871 °C to 982 °C, led to an increase in the low cycle fatigue behavior of coated Rene®80 about 10% as compared to the uncoated specimens.