<p>This study investigates the failure mechanisms of the damping element (interconnection tube) that connects the first stage grouped blades in an industrial gas turbine. The component is made of Inconel 718 (IN718), which is a nickel-based superalloy that strengthens through precipitation and is well known for its excellent performance under high temperature and corrosive environments. The tube failed prematurely under combined thermal and mechanical loading after extended service. Visual inspection and scanning electron microscopy revealed multiple degradation modes, including erosion, surface oxidation, fatigue striations, and intergranular cracking. Chemical and microstructural analyses, along with hardness measurements, confirmed that the failure was not caused by bulk material degradation. Finite element simulations showed a concentration of stress near the eroded regions, which correlated with the observed crack initiation sites. The loss of structural integrity in the damping element increased local stress at the blade root and reduced the fatigue safety factor by approximately 22%. These findings emphasize the combined effects of surface oxidation, erosion, and vibratory loading on fatigue driven failure in turbine blade assemblies.</p>