Capacitor discharge welding of Ta1 and 0Cr18Ni9 thin plates

Capacitor discharge spot welding with rapid solidification characteristics of Ta1 and 0Cr18Ni9 thin plates were carried in present paper. The microstructure and properties of the welding joints between by direct CDW and adding Fe₅Co₂₄Ni₂₇Cu₂₅Cr₁₉ interlayer alloy were analysed and discussed. The results show that the solute trapping can effectively inhibit brittle intermetallic compounds to realize welding tantalum and steel welding. The welding joints of the direct CDW possess hyperbolical and gyro shaped and the melting zone is located in one side of the 0Cr18Ni9 plate. Nuggets appear about 0.2 mm subcircular porosity in diameter, and Fe₅Ta₃ and Cr₂Ta intermetallic compounds are produced at the interface between tantalum and steel. The welding joint added high entropy interlayer alloy is composed of cap-shaped nugget and fusion area of the transition base metal. Furthermore, the nugget have simple solid solution structure and fine microstructure which consisted of columnar crystals. Under the same condition, shear strength of the joint is 239 MPa by direct spot welding of Ta1 and 0Cr18Ni9 and the higher shear strength of Ta1/0Cr18Ni9 spot welding joint by CDW reached 374 MPa.