6. The Effect of Preliminary Laser Surface Treatment on the Mechanical Properties of a Solid-Phase Compound of an Iron-Nickel Alloy in Diffusion Welding

Laser micro- and nanostructuring is used in various fields of science and technology, because it can improve different surface properties. The chapter considers a method of direct laser micro- and nanostructuring of metallic surfaces and an effect of such preliminary laser surface treatment on the mechanical properties of solid-phase joints made by diffusion welding. For laser treatment it is proposed to use scanning beam of Nd:YAG laser with a wavelength of 355 nm. Analysis of surface topography of samples treated by nanosecond laser was performed by optical profilometer. After the diffusion welding tensile tests were performed on conjunction samples cut out from welded workpieces. These tests showed that preliminary laser processing of the surface of samples made of nickel alloy leads to an improvement in the mechanical properties of the conjunction obtained by diffusion welding. It leads to an increase in the tensile strength up to 29% and tensile strain up to 20%. The pulse energy density at laser surface treatment significantly affects the properties of welded joint. Also the preliminary laser treatment of surfaces allows one to reduce the temperature of diffusion welding.