High-temperature materials testing with full-field strain measurement: experimental design and practice

Understanding material behavior at high temperatures is critical for aerospace and energy applications. Prior research has shown that ceramic composites degrade under thermomechanical stress. However, capturing strain data at extreme temperatures remains difficult. Illumination and heat haze interfere with imaging. Surface contrast diminishes at elevated temperatures. These factors limit the accuracy of strain measurements. Conventional methods struggle to provide full-field data. No prior work had resolved these imaging limitations. This gap motivated the development of new experimental techniques.

The goal was to improve strain measurement in ceramic composites at high temperatures. The specific problem is the lack of reliable full-field strain data. Traditional methods fail due to heat haze and poor surface contrast. The motivation is to enable accurate thermomechanical characterization. This study aimed to test new imaging techniques. The focus was on non-contact strain measurement. The target materials included a Ni-based superalloy and a C/SiC composite. The ultimate aim was to validate these methods up to 1500 °C.

The researchers used a laser heating facility to simulate high-temperature environments. Digital image correlation was applied for strain measurement. This approach avoids physical contact with the specimen. The setup included controlled lighting to counteract heat haze. Surface contrast was enhanced using specialized coatings. The tests involved both static and dynamic loading conditions. Data was collected at multiple temperature intervals. The methods were tested on two distinct materials for validation.

The new methods enabled full-field strain measurement up to 1500 °C. Digital image correlation provided consistent strain data. Surface contrast was maintained using reflective coatings. Heat haze was minimized through controlled lighting. The Ni-based superalloy showed expected strain behavior. The C/SiC composite exhibited unique thermal deformation patterns. Strain distribution was mapped across the entire surface. The results suggest that these techniques are reliable for high-temperature testing.

The study demonstrated that digital image correlation works at extreme temperatures. The methods resolved issues with heat haze and surface contrast. The results suggest that these techniques can be applied to other ceramic composites. The researchers propose that these methods improve material characterization accuracy. The study supports the use of non-contact strain measurement. The findings may help in designing materials for high-temperature applications. The authors suggest that further testing on additional materials is warranted. The study contributes to the field of thermomechanical testing.