Investigation of multiaxial fatigue in the prospect of turbine disc applications: Part I – Experimental setups and results

An experimental study is presented for two alloys commonly used for compressor and turbine discs in the context of fatigue crack initiation. It includes classical uniaxial tests together with multiaxial ones, both in tension-compression torsion, in tension-internal pressure and in biaxial loads applied on a specially designed cruciform specimen. The experimental devices including heating system are presented. The specimens design and the associated specific testing procedures are also described. Some results with crack observations are discussed here within a thermoelastic approach. Nevertheless multiaxial fatigue criteria based on results of cylic viscoplastic calculations are analyzed in Part I