Creep lifing methodologies applied to a single crystal superalloy by use of small scale test techniques

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2015-06, Vol.636, p.529-535
• Main Authors: Jeffs, S.P., Lancaster, R.J., Garcia, T.E.
• Format: Article
• Language: English
• Subjects: Correlation; Creep; Creep (materials); Finite element method; Mathematical analysis; Mathematical models; Punches; Single crystal; Single crystals; Small punch; Superalloys; Wilshire equations
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2015.03.119

In recent years, advances in creep data interpretation have been achieved either by modified Monkman–Grant relationships or through the more contemporary Wilshire equations, which offer the opportunity of predicting long term behaviour extrapolated from short term results. Long term lifing techniques prove extremely useful in creep dominated applications, such as in the power generation industry and in particular nuclear where large static loads are applied, equally a reduction in lead time for new alloy implementation within the industry is critical. The latter requirement brings about the utilisation of the small punch (SP) creep test, a widely recognised approach for obtaining useful mechanical property information from limited material volumes, as is typically the case with novel alloy development and for any in-situ mechanical testing that may be required. The ability to correlate SP creep results with uniaxial data is vital when considering the benefits of the technique. As such an equation has been developed, known as the kSP method, which has been proven to be an effective tool across several material systems. The current work now explores the application of the aforementioned empirical approaches to correlate small punch creep data obtained on a single crystal superalloy over a range of elevated temperatures. Finite element modelling through ABAQUS software based on the uniaxial creep data has also been implemented to characterise the SP deformation and help corroborate the experimental results.