Structural and Mechanical Evaluation of Dissimilar Bonding of IN۶۲۵/SS۳۱۶L Using BNi-۲ Interlayer and TLP Bonding Technique

In this study, the bonding of IN۶۲۵ superalloy to ۳۱۶L stainless steel was investigated using the transient liquid phase (TLP) bonding process with a BNi-۲ interlayer. To evaluate the effect of temperature on the microstructure, hardness, and shear strength of the joint, the bonding process was carried out at three temperatures of ۱۰۸۰°C, ۱۱۳۰°C, and ۱۱۸۰°C for a constant duration of ۶۰ minutes. Microstructural examinations using optical and scanning electron microscopies (SEM) revealed the formation of nickel-boron-rich intermetallic compounds as well as chromium carbides (Cr₂₃C₆) in the joint region. The formation of these compounds led to an increase in hardness of the diffusion affected zone (DAZ) and the non-isothermal solidification zone (ASZ). Additionally, shear strength test results indicated that the joint strength increased from ۲۰۰ MPa for the sample bonded at ۱۰۸۰°C to ۳۵۰ MPa for the sample bonded at ۱۱۸۰°C. The reduction of brittle eutectic phases and the increased uniformity of the formed phases in the joint region played a key role in improving the mechanical properties of the joint. This study demonstrates that the TLP process with a BNi-۲ interlayer is capable of producing strong and stable joints in dissimilar superalloy to stainless steel bonds, and the optimal selection of temperature and time parameters can significantly enhance the mechanical and structural properties of the joint .

کلیدواژه ها:

IN۶۲۵ ، TLP ، SS۳۱۶L ، Microstructure ، Solidification ، Strength.