Abstract

    For the past 3-4 years work has been undergoing on the development of a new computer programme (JMatPro) for calculating general material properties of multi-component alloys.These properties are wide ranging, including stable and metastable phase equilibria, thermophysical and physical properties (from room temperature into the liquid state), TTT/CCT diagrams, martensite temperatures, proof and tensile stress, hard-ness, stress/strain diagrams,etc. A feature of the new programme is that the models are based on sound physical principles rather than purely statistical methods. Thus many of the shortcomings of methods such as regression analysis can be overcome. For example, sensitivity to microstructure can be included. Prediction of physical properties relevant to solidification can now also be made,which is of vital importance for process simulation but extremely difficult to measure or otherwise estimate. This paper provides a background to the scientific models used by JMatPro and numerous examples of calculated results for various properties in Ti-based alloys will be presented, with the emphasis being placed on validation of calculated results against experimental observation in multi-component commercial alloys.

1 Introduction

    Thermodynamic modelling tools for exploring equilibrium phase relationships in complex materials are being increasingly used in industrial practice [1]. Such calculations benefit the end user, whether they work in industry or academia, but the applicability of phase equilibrium calcul-ations often falls short from directly providing the information that is actually required. For example, thermodynamic modelling helps towards the understanding of changes in phase constitution of a material as a function of composition or temperature.However, a considerable jump is then needed to convert this information into the properties being targeted by the end user, e.g. TTT/CCT diagrams, mechanical properties, thermophy-sical or physical properties.

    To overcome these limitations a new computer programme has been developed, called JMatPro, an acronym for Java-based Materials Proper-ties software. The approach adopted in the development of the new programme has been to augment the thermodynamic calculation by incorpor-ating various theoretical models and additional property databases that will allow a quantitative calculation for the requisite materials property within a larger software.To be published in “Ti-2003: Proc 10th World Conference on Titanium, July 13-18, Hamburg, Germany” structure. This then enables a clear path to be created between the thermodynamic calculation and the final product that is required, i.e. the materials property itself.

    The purpose of the present paper is to demonstrate how the translation from thermodynamic calculations to general materials properties has been achieved and to present examples of applications to multi-component commercial alloys, with particular emphasis on the validation of the calculated property against experimental values.

``````