Profilometry-based indentation plastometry (PIP) integrated finite element (FE) model validation using neutron diffraction

Stress assisted corrosion can lead to premature failure of structural alloys such as stainless steel 316. The mechanisms governing the various failure modes are poorly understood due to the complexities involved in testing the combined effects of stress and corrosion at high temperatures. Modified Turski (MT) specimens are an invaluable tool for studying these mechanisms as they can be pre-stressed to induce residual stresses and exposed to a corrosive environment without needing specialised equipment. However, it is challenging to measure the stresses experimentally without altering the stress state. To overcome this, finite element (FE) modelling can be used, but validated models are scarce, particularly for MT specimen geometry. In this work, an FE model was developed based on the non-destructive characterisation of material using profilometry-based indentation Plastometry (PIP) and validated for residual stresses using enhanced neutron diffraction (ND) measurement. The model results showed significant correlations with experimentally observed deflection and residual stress profile. The deviation observed between the model and experiment was analysed and discussed to understand the evolution of strain field in materials. To conclude, this validated model, and approach is reliable and enables rapid material compatibility assessment for stress assisted corrosion, which is particularly important in emerging industries like concentrated solar thermal (CST) and hydrogen energy, amongst many others. • Modified Turski (MT) specimen design to study stress assisted corrosion. • Profilometry-based indentation Plastometry for material characterisation. • FE model validation using compression tests and neutron diffraction measurements. • Evolution of plastic strain field leading to deviation in measured stress values. • Rapid method for material compatibility assessment for critical infrastructure.