DOUBLE SHEAR CREEP TESTING OF SUPERALLOY SINGLE-CRYSTALS AT TEMPERATURES ABOVE 1000-DEGREES-C

The present paper describes a technique for double shear creep testing of superalloy single crystals (SX) at temperatures above 1000 degrees C. From an engineering point of view this method is interesting because shear testing represents a simple case of multiaxial loading and because creep anisotropy can be easily assessed. In the case of SXs pure shear loading allows to directly activate specific crystallographic slip systems and this makes the method attractive from a fundamental point of view. The paper highlights all important experimental aspects which must be considered in the development of a double shear test. In addition finite element creep calculations were performed to study shear and bending stresses for isotropic material behaviour. Preliminary mechanical and microstructural results, which show the viability of the technique are presented.