Spark Plasma Sintering (SPS) and Spark Plasma Welding (SPW) represent innovative techniques for joining dissimilar materials. These methods allow for the controlled manipulation of processes such as atomic diffusion, phase transformation, and grain boundary modification to create various components. Titanium and its alloys are ideal candidates for electrolytic solvents in reactor fuel reprocessing plants due to their outstanding corrosion resistance. Similarly, austenitic stainless steel 316 is widely utilized in sectors such as petrochemical, aerospace, and nuclear energy, thanks to its high strength, weldability, ductility, and corrosion resistance. In nuclear power plants, on-site joining of austenitic stainless steel 316 and titanium alloys is often necessary. However, direct fusion welding between stainless steel and titanium poses significant challenges due to the unavoidable formation of brittle intermetallic compounds between iron and titanium, which can cause cracking and weaken the tensile and bending strength of the joint. Therefore, solid-state welding presents the most viable solution for this type of joint. Various solid-state welding techniques, including diffusion bonding, friction welding, and explosion welding, have been explored previously, but with limited success. This research aims to examine the microstructure and mechanical properties of the joint formed between austenitic stainless steel 316 and the Ti-6Al-4V titanium alloy using the spark plasma sintering method. Joints were created at temperatures of 600℃, 650℃, 700℃, 750℃, 800℃, and 850℃, applying a pressure of 30 MPa and maintaining a hold time of 5 minutes. The microstructure of the welded joints was analyzed using an optical microscope, and void content was quantified for both austenitic stainless steel 316 and the Ti-6Al-4V alloy. Additionally, the grain size and microstructure of both alloys were investigated using etching techniques. Scanning electron microscopy was employed to eva‎luate the phases and layers formed at the bond interface, and the thickness of these layers was measured. At 850 degrees Celsius, a continuous formation of the Fe-Ti intermetallic compound was observed. The tensile and bending properties of the joint were assessed at 700, 750, and 800 degrees Celsius, revealing a maximum tensile strength of 36.2 MPa and a bending strength of 792 MPa at 800℃. The fracture surfaces of the samples were also analyzed.

علي شفيعي

رضا اميني نجف آبادي

عباس بهرامي , علي اشرفي