Creep-Fatigue Tests on Full Scale Directionally Solidified Turbine Blades

A new experimental method, in which a full scale directionally solidified (DS) alloy turbine blade is loaded by a special design rig employing friction force and heated by eddy current induction, is proposed to conduct creep-fatigue life tests in this investigation. The method can take factors such as geometry, volume, especially cast procedures, etc., into creep-fatigue life assessment. Principle and design of the test rig are fully explained. Creep-fatigue tests of turbine blades made of DZ4 alloy (one type of DS alloys) were conducted and test data were analyzed. Life prediction based on test data of this investigation shows good agreement with actual flight experience of these blades. The method of this article provides a new way to estimate the potential creep-fatigue or low cycle fatigue life for turbine blades.