Synchronous measurement of full-field temperature and deformation at high temperature especially more than 1273 K is of much significance especially for part applications of turbine structures and materials. Non-contact optical methods attract more and more attention, however, current methods all face different challenges, such as strong light reflection on the surface of the specimen, disturbing radiation from environment, complex equipment setup, limited measured temperature not higher than 900 °C and so on. In this work, we develop an innovative technique to overcome some current problems. The measurement system employing an ultraviolet (UV) imaging system is composed of a scientific complementary metal oxide semiconductor (sCMOS) camera, a lens and a UV bandpass filter. The UV bandpass filter was used for thermal radiation elimination to acquire high quality images at elevated temperatures for deformation field calculation suitable for digital image correlation (DIC) method. The UV sensitive sCMOS camera without using active illumination was employed to collect enough UV radiation energy and eliminate the interference of the external ambient light, which is applicable for high accuracy temperature field measurement. Our system can realize the synchronous capture of image and temperature acquisition with passive UV imaging system at temperature not lower than 1473 K. The feasibility of the method was verified through heating molybdenum (Mo) and Ni-based superalloy IC21 materials. The temperature fields of Mo measured by the established imaging system up to 1835 K with error less than 0.25% showed the effectiveness for temperature measurement. The estimated deformation and temperature field of Ni-based superalloy IC21 up to 1473 K with measured temperature error less than 0.5% demonstrated well the great potential of the UV imaging system in simultaneous measurement of temperature and deformation fields at elevated temperatures.

The hollow twin-web disk is designed to improve the thrust-to-weight ratio of the aero engine, where the welding joint microstructures determine the disk’s mechanical properties. This study aimed to elucidate the effect of abnormal grains formed in the welding region on the mechanical properties of FGH96 solid-state diffusion bonding joints. Digital image correlation using images captured by scanning electron microscopy (SEM-DIC) and electron backscattering diffraction (EBSD) technologies were applied. The results show that abnormally large grains (2.5 times that of the matrix), with preferred orientation in the bonding region, were detrimental to the joint mechanical properties. The yield and tensile strengths were 995.85 MPa and 1456.67 MPa, respectively, and the corresponding relative (ratio to the matrix) ones were 92.54% and 88.81%. After modifying the bonding process, the grain size in the bonding region was tailored to close to that of the matrix, and considerable twin boundaries (TBs) formed, leading to the relative tensile and yield strength reaching 98.86% and 99.37%. Furthermore, the failure mode changed to intragranular type from intergranular type. It demonstrates that tailoring the newborn grain size, introducing TBs inside, and eliminating preferred orientation during the welding process can be an efficient way to improve the joint mechanical properties.