Abstract

High-temperature turbine blades in gas and steam turbines operate under severe mechanical, thermal and environmental stresses. Conventional materials like stainless steel (SS304) and nickel-based super alloys (SU718) face limitations in creep resistance, oxidation and corrosion. To address these challenges, this research develops a cost-effective hybrid SU718-SS304 material produced through Tungsten inert gas welding (TIG) and Wire Arc Additive Manufacturing (WAAM), with improved mechanical and thermal properties. Thermal analysis was conducted using Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA), and the results showed that the fusion zone between the materials had a melting temperature of 1286 °C, as opposed to 1231 °C for SS304 and 1447 °C for SU718. As revealed by mechanical characterization tests, the hybrid material’s fusion zone exhibited ultimate tensile strength of 295 MPa, which was less than that of SU718 (641 MPa) and SS304 (559 MPa), but still suitable for turbine applications where cost-performance optimization is essential. Furthermore, specimens were analysed using Scanning Electron Microscopy (SEM) both prior to and following fracture in order to investigate the failure causes and microstructural features. The hybrid material exhibited remarkable corrosion resistance, showing a weight loss of only 0.094 g and a corrosion rate of 27.68 mpy in the fusion zone. The combination of balanced mechanical properties, cost-effectiveness, and thermal stability indicates the potential for high-temperature turbine applications, pending comprehensive high-temperature mechanical validation, including creep, fatigue, and thermal cycling tests under realistic operating conditions.

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