Design of a creep resistant nickel base superalloy for power plant applications: Part 1 - Mechanical properties modelling

Abstract

Models have been developed and used as tools to design a new 'made to measure' nickel base superalloy for power plant applications. In Part 1, Gaussian processes are used to model the tensile and creep rupture properties of superalloys as a function of their composition and processing parameters, making use of large databases on existing alloys. The models are able to estimate the actual influence of alloying elements on the mechanical properties over a wide range of temperature and stress. They have been used, in conjunction with general metallurgical concepts and industrial requirements, as a basis for the design of a new Ni-Cr-W-Al-Ti-Fe-Si-C-B superalloy with desirable properties. It is estimated that the proposed forgeable and weldable alloy should have a creep rupture life at 750° C of 100 000 h under a stress of 100 MPa, with a huge reduction in price compared to existing commercial alloys with similar properties. In a following paper, Part 2, an attempt is made to design against the formation of undesirable phases and chemical segregation, using phase diagram calculations. Preliminary experimental results are presented in Part 3.