Optimization of the diffusion bonding process for a multilayer joint in 14Cr17Ni2 alloy

Abstract

Purpose. To optimize diffusion bonding technology for multilayer joints of aircraft engine components made of 14Cr17Ni2 alloy, minimizing material degradation and geometric distortions. Research methods. Analysis of conventional (T1) and intensified (T2) diffusion bonding (using an intermediate nickel layer up to 10 μm). Parameters were optimized on laboratory samples and full-scale models; joint quality was assessed by metallographic analysis. Results. T1 technology requires high pressure (15–20 MPa) at 950–1050 °C. Optimized T2 technology (with a Ni layer) showed superior results: welding temperature 950 °C, pressure 5 MPa, holding time 50 min. The Ni layer allowed for a 3-4 fold reduction in pressure, use of a lower welding temperature, maintained high joint quality, and ensured deformation ≤4%. Metallography confirmed the absence of defects in the microstructure. The reduced welding tempera-ture of 950°C prevents post-weld hardening of the 14Cr17Ni2 alloy. Scientific novelty. Optimal parameters for diffusion welding of multilayer joints of 14Cr17Ni2 alloy at low pressure using a thin Ni interlayer have been determined, ensuring defect-free, high-quality joints with significantly reduced weld-ing pressure and temperature. The optimal interlayer thickness allows leveraging the contact strengthening effect to achieve a joint with strength comparable to the base material. Practical value. T2 diffusion bonding technology ensures reliable manufacturing of precision multilayer compo-nents from 14Cr17Ni2 alloy with minimal thermo-mechanical impact and reduced manufacturing complexity (lower pres-sure equipment). This is a promising and economically viable solution for the aviation industry, for components requiring high precision and performance under extreme conditions.