Weldability of superalloys Hastelloy X by Yb : YAG laser

International audienceRequirements of aircraft parts welded becoming increasingly severe especially in termsof reproducibility of geometry and metallurgical grade of weld bead; laser welding is a viable method of assembly to meet these new demands by its automation to replace longer term the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X alloy by the butt welding process Nd: YAG laser. To identify influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas) while streamlining testing, an experimental design was established with the CORICO software that uses the graphic correlation method. The position of the focal point was fixed at -1/3 of the thickness of the sheet. The gas flow rate and the power of the beam seem to have a major role on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of base metal. However, there is a significant drop in the elongation at break of about 30 %. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show generally a molten zone presenting dendritic large grain compared to the equiaxed grains of the base metals without a heat affected zone