Investigating the properties and characteristic analysis of frictionally welded dissimilar Inconel alloys

Friction welding of Inconel 625 and Inconel 825 alloys is crucial for high-performance applications like turbocharger shafts, where high tensile strength and corrosion resistance are essential. This study evaluated the key aspects of the welding process and the resulting mechanical properties of the joints. Among the samples, Sample S3—welded at a spindle speed of 2350 rpm, soft load of 700 Nm, and friction load of 1300 Nm—demonstrated the most favorable mechanical properties, with a tensile strength of 641.63 MPa, yield stress of 540.11 MPa, and elongation of 17.86%. These values align with or exceed the mechanical properties reported in similar studies on friction welding of Inconel alloys, where tensile strengths typically range between 600 and 652 MPa. Scanning electron microscopy (SEM) analysis revealed no visible cracks in Sample S3, confirming the quality and integrity of the welds. Additionally, electron backscatter diffraction (EBSD) analysis provided a deeper understanding of the microstructural characteristics, revealing a refined grain size of around 10 microns and uniform grain structure with 52.15% high-angle grain boundaries minimal anisotropy, which further contributes to the material's strength and reliability. The optimization of welding parameters has allowed the identification of ideal conditions for achieving superior mechanical properties. This study demonstrates the efficacy of the friction welding process for Inconel alloys, highlighting its potential for economically viable and sustainable applications.