Design of a creep resistant nickel base superalloy for power plant applications - Part 3 - Experimental results

A semi-industrial scale rolled bar of the creep resistant Ni base superalloy designed in Parts 1 and 2 has been fabricated. The influence of heat treatment on microstructure and phase formation has been investigated using both optical and electron microscopy, and X-ray diffraction. Mechanical properties at ambient and high temperature have been measured by hardness testing, compression testing, and tensile creep testing. These experimental results are in good agreement with the predictions of Parts 1 and 2 concerning phase formation, yield stress and creep rupture stress. The target of a lifetime of 100 000 h at 750degreesC under 100 MPa seems attainable. The design procedure is therefore mainly validated, and results in a promising new alloy for power plant applications.