Application of Digital Image Correlation Method in Titanium Alloy Tension and Poisson’s Ratio Tests at High Temperature

Testing and characterization of mechanical properties of aeronautical materials is the premise of their engineering application, and deformation measurement is an important part of mechanical properties testing of materials. The strain measurement of new aeronautical materials faces many new challenges. Non-contact full-field optical deformation measurement of materials can be achieved effectively by using digital image correlation (DIC) method. In the present work, DIC method was used to measure the tensile full stress-strain curves and Poisson’s ratios of TC4 titanium alloy at 100~350 ℃. The results show that the tensile strength, conditional yield strength and elastic modulus of TC4 titanium alloy decrease with the increase of test temperature. Their retention rates at 350 ℃ are 82.8%, 71.7% and 79.5% respectively, indicating that TC4 titanium alloy has good temperature resistance. The plasticity of TC4 titanium alloy increases with the increase of temperature. Comparing the Poisson’s ratio data of TC4 titanium alloy with the data of materials manual, all errors are less than 6%, indicating that DIC measurement accuracy can meet the Poisson’s ratio test requirements of TC4 titanium alloy, and the measurement data can well reflect the mechanical properties of the material.