Fabrication of microscale heat-resistant grating for in-situ high temperature deformation measurement by sampling moiré method

The weak quality of conventional gratings at high temperatures severely limits the application of grating-based methods for high temperature deformation measurements. In this study, a grating fabrication technique with heat-resistant and high adhesion for microscale deformation measurement was proposed. By using UV lithography and metal magnetron sputtering, heat-resistant grating with a pitch of 8 μm was fabricated on the surface of Ni based single-crystal superalloy (NBSC) specimens. Then, the quality of gratings at different magnetron sputtering times was discussed to optimize the fabrication parameters. In application, a high temperature in-situ mechanical experiment system was employed to perform in-situ heating and tensile experiments on NBSC specimens. The results show that the heat-resistant grating maintains excellent contrast and integrality at room temperature (RT) to 1000 °C. The full-field deformation of the NBSC specimen under tensile loading at 900 °C was quantitatively measured by the sampling moiré method, which clearly demonstrates the evolution of plastic localization at the microscale. The heat-resistant grating fabrication technique proposed is simple and easy to implement, showing a promising potential for microscale high temperature deformation engineering applications.