Thermal Stress-Strain Behavior of Cu on Metallized Si3N4 Substrate Under Thermal Cycling Test by Digital Image Correlation

This research presents an in-situ measurement of thermal strain in metallized <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Si}_{3}\mathrm{N}_{4}$</tex> substrate during consecutive cycling tests, ranging from cycles <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\sim 2$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$199\sim 200$</tex> with temperature varying from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-40{}^{\circ}\mathrm{C}$</tex> to 250 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${}^{\circ}\mathrm{C}$</tex>. Based on the thermal strain curves, the residual stresses of constituent components were calculated, assuming no defect occurred in the substrate. The residual stress of Cu obtained in this study showed good agreement with the stress-strain behavior of Cu observed in tension and compression tests. The results validate the use of DIC method for evaluating the stress-strain behavior of composites under thermal cycling conditions.