Modelling the Material Properties and Behaviour of Ni- and NiFe-Based Superalloys

Abstract

Over the past decade thermodynamic models have become increasingly used for Ni-and NiFebased superalloys. However, their applicability often falls short from directly providing the information that is actually required. To overcome such limitations a new computer programme has been developed, called JMatPro (an acronym for Java-based Materials Properties software). The properties which can be calculated are wide ranging, including thermo-physical and physical properties (from room temperature to the liquid state), TTT/CCT diagrams, coarsening of ' and ", and mechanical properties. It should be noted that the mechanical properties are calculated as a function of temperature and strain rate up to the melting point. Stress/strain diagrams at any given temperature and strain rate can also be generated. The creep properties that JMatPro provides include steady creep rate, rupture life and rupture strength. A feature of the new programme is that the calculations are based, as far as possible, on sound physical principles rather than purely statistical methods. Thus many of the shortcomings of methods such as regression analysis can be overcome. It allows sensitivity to microstructure to be included for many of the properties and also means that the true inter-relationship between properties can be developed, e.g. in the modelling of creep and precipitation hardening. The purpose of the present paper is to describe the technical background behind the new programme, giving extensive examples of its application and use for superalloys of the 718, 625, 706 and derivative types.

A New Ni-Base Superalloy for Oil and Gas Applications

“…The heats that showed potential were tested for tensile, impact, hardness, and microstructure. To begin with, a thermodynamics based software, JMatPro [10], was used to simulate some of the potential chemical compositions. This software predicts variation of strength with chemical composition.…”