Customized High-Temperature Bending with DIC for High-Throughput Determination of Creep Parameters: Technique, Instrumentation, and Optimization

Abstract

Bending is emerging as an alternative to uniaxial testing for high-throughput determination of primary-cum-secondary creep parameters. This is feasible because of augmentation of cantilever bending tests with digital image correlation (DIC). Here, we provide guidelines for selecting the patterning medium, spray conditions, and other important parameters for laying high-resolution, high contrast ratio DIC speckle-patterns that are optimal for long-term creep tests performed up to 800°C. Furthermore, an experimental setup for efficiently performing creep experiments in bending at high temperatures is designed and developed. Proper choices of paint, spraying technique, high-resolution image capturing device, and the appropriate heat management system in the mechanical testing unit yield unambiguous correlation in the “DIC augmented bending creep” tests. The developed methodology and the equipment are validated by evaluating the creep behavior of a stainless steel at 750°C by obtaining multiple stress–strain rate pairs from a single test. An excellent match between uniaxial and bending data is observed, thereby paving the way for using DIC augmented bending creep for studying the creep response of materials at high temperatures in a high-throughput fashion.