Materials Science and Structural Integrity (SI) Assessment

Future industry in the nuclear, chemical, aero and the energy sector in gegeral, needs to operate under more stringent operating conditions both safely and in a cost effective manner in order to improve efficiencies and reduce emmisions. This means materials will have to see higher operating loads and temperatures under more corrosive environments.

In order to effectively solve the future problems within a shorter time span a fundamentally different approach is needed. Thus materials science and Structural Integrity (SI) assessment will need to be integrated at both the research and industrial levels. This will involve the coming together of a number of cross-disciplines that should develop in parallel in order that more advanced materials and components under harsher operating conditions can be developed more rapidly.

The goal of the material scientist is to understand the development and fabrication mechanism of the complex alloys that need to be produced and improve their mechanical properties from a fundamental understanding of the sub-microstructural response of the material to composition and heat treatment changes. Structural integrity is concerned with determining and predicting the performance, failure, durability and safety of the component fabricated from the material that is subjected to a range of operating conditions during use. The principal disciplines involved in predictive structural integrity are materials modelling, stress analysis, inspection techniques and experimental validation.

The damage due to material heat treatment, welding, aging and alloy degradation, creep and fatigue will show a different failure macro-response for different size components and loading conditions. Hence it is not sufficient to understand the failure mechanism under the nano or micro structural level to predict component failure but to integrate the material physical understanding to the failure response of the structural. Therefore research needs to develop a multiscale link between, materials development, laboratory testing, failure mechanisms, predictive numerical modelling, component operating conditions, loading history and correlating parameters. This will allow a faster cycle for developing improved and optimised predictive models of alloy production all through to components operating safely in extreme conditions feeding back to further improved alloys.

It is imperative therefore that the multiscale approach needed for this task can be rapidly developed as future more efficient and low greenhouse CO2 emission technology which will operate under higher temperatures is already in demand worldwide. A step-change in the fundamental understanding of the material and component interaction is therefore needed. For example the failure mechanisms due to corrosion, fatigue, creep and elastic/plastic fracture and collapse in the material at different length scales needs to be understood and quantified before improvements in the failure prediction of components can be optimised. To a great extent the rapid advancement in materials development especially nano-technology, improved computational models and advanced measuring and testing techniques will allow the implementation of much improved safe operating criteria of components.