CO₂ Laser Welding Of 7075 High Strength Aluminum Alloy With Filler Wire

7075 High strength aluminum alloys have the highest strength in room temperature which has very wide range of engineering applications, including aerospace, automobile, light railway traffic etc. Since these alloys are difficult to be welded with common welding methods and not recommend for welding ,they are usually joined by bolts and rivets when assembled as structures .such mechanical joints increase structure weight and economy energy cost. Laser beam has higher power intensity, there is an increasing interest in applying laser beam welding to aluminum alloys since it offers advantages such as high welding speeds and low distortion. However, porosity and hot crack are often encountered in laser welding as well as in conventional processes. To overcome the problems, a practical method filler wire has been used in the laser welding process. The main content of this pape is experimental studying on laser welding for 7075 Aluminum alloy using filler wire. To meet the specialty of laser filler wire welding, a three-ply self-bundling coaxial filler wire head which can both feed the wire metal and provide shielding gas was designed .the experiments show that the coaxial filler wire head can meet the demand required by welding with filler wire.The quality of welding seam is high, no micro-flaw such as undercut, excessive penetration and discontinuous etc. The results of high speed video camera show that the moving of the welding process with filler wire is more steady and uniform than that without filler wire. By metallographic analyzing, metallic vapor and plasma is effectively compressed. Adopting optimized processing parameters we have welded 7075 aluminum successfully by filler wire metal to the welding pool with high power CO₂ laser, welding with filler wire AlSi₁₂ can well elimimate hot crack and porosity,the tensile strength of samples with and without post process is 360.81 Mpa and 440.5Mpa, respectily. The average tensile strength of the 7075(T6) Al alloy...