## 1 Introduction  
Due to its excellent properties, the high-strength superalloy Inconel718 finds extensive use in high-temperature applications, such as turbine blades, jet engines, gas turbine applications, and disk materials. These properties include good weldability, corrosion resistance, oxidation resistance, excellent resistance to crack formation, and high creep strength at elevated temperatures [1; 2]. The primary strengthening mechanism in this alloy results from coherent disc-shaped particles of \(\gamma^{\prime\prime}\) (Ni\({}_{3}\)Nb) precipitates. The good weldability of these superalloys is attributed to their resistance to strain age cracking, which arises from the sluggish precipitation kinetics of the \(\gamma^{\prime\prime}\) phase. This slow age-hardening effect results in a relatively high ductility and low strength in the HAZ during the initial aging treatment, which allows the residual stresses to relax and reduces the propensity for strain-age cracking [3]. Austenitic stainless steels are extensively used in nuclear and petrochemical environments, due to their excellent mechanical performance at higher temperatures. These steels also possess good corrosion and oxidation resistance. These steels are classified as \"L\" grades, \"straight\" grades, or \"H\" grades, based on their carbon content. The L grades have a carbon content of 0.03%, the straight grades have a carbon content of 0.03-0.08%, and the H grades have a carbon content of 0.04-0.10%. The high carbon content in H grades makes them much harder and more wear-resistant. Due to the additional carbon content, the H grades can retain their strength and hardness at higher temperatures, which makes them suitable for high-temperature applications. However, an increase in carbon content also results in poor weldability of the steel. The low carbon percentage of L grades is explicitly designed to increase weldability. Low-carbon stainless steels such as SS304L are commonly used to avoid intergranular corrosion [4]. Ni-Fe superalloys are used for various structural applications in aerospace, nuclear power plants, and chemical industries. Joining these alloys to stainless steels is common, and the demand for economical and efficient materials frequently involves joining dissimilar metals. Inconel718 alloy is expensive, and a bimetallic junction with low-cost components is economical. Steel is a high-strength, low-cost structural material [5]. SS304L is the most frequently used austenitic stainless steel, known for its excellent strength and corrosion resistance properties. Although bolts and mechanical fasteners can be used to join superalloys with stainless steel 304L (alloy steels) for different applications, welding techniques are preferred for creating dissimilar metallurgical joints, because mechanical joints tend to exhibit poor fatigue performance. Conventional fusion welding techniques have many problems, such as Laves phase, boron/niobium segregation, and micro-fissures (liquation cracking) in the fusion zone or HAZ of IN718 welds [3]. Laves is a brittle intermetallic phase that negatively impacts the mechanical properties. To avoid the solidification-related problems associated with fusion welding, solid-state welding processes such as friction welding are preferable. Welds joined by friction welding are free of porosity, segregation, and liquation cracking, as melting and solidification are not involved in this process. [PERSON] et al. [6] compared the effects of welding processes on the microstructure and mechanical properties of dissimilar austenitic (AISI 304)-ferritic (AISI 430) stainless steel weld joints. They found that friction welding dissimilar AISI304/AISI 430 welds displayed greater pitting corrosion resistance compared to welds prepared using fusion welding techniques (GTAW, EBW). This was owing to the low occurrence of carbides in the friction weld microstructure in similar and dissimilar welds. Standard heat treatment of superalloy Inconel 718 consists of solution treatment and aging. [PERSON] et al.