Study of the size difference in laser-welding spots of aluminum alloy

During laser spot welding of an Al-Fe alloy, there is a size difference in welding spots under the same sheet-surface condition and the same welding parameters.The microstructures of the surface of the Al-Fe alloy sheet before and after laser welding are analyzed by means of a light microscope (LM) and electron probe microanalysis.It is found that, compared with small welding spots, at the micro-zone where the welding spots are larger, the content of intermetallic compounds (IMCs) is higher before the welding and the contents of Fe and Mn, which constitute IMCs, are also higher after the welding.The results show that the distribution of IMCs in the sheet surface affects the size of laser-welding spots.The difference in the distribution of IMCs at the micro-zone of the sheet surface causes the difference in the size of the welding spots.Keywords: laser spot welding, Al-Fe alloy, welding spot, intermetallic compound Med laserskim to~kovnim varjenjem (punktiranjem) plo~evine iz Al-Fe zlitine, nastajajo razli~no velike varilne to~ke pri na~eloma enaki vizualni povr{ini plo~evine in enakih parametrih varjenja.Zato so avtorji analizirali mikrostrukturo povr{ine plo~evine iz Al-Fe zlitine z opti~nim mikroskopom (LM) in elektronskim mikro-analizatorjem vzorcev (EMPA).Analize so izvajali pred in po to~kovnem laserskem varjenju.Ugotovili so, da v primerjavi z majhnimi varilnimi to~kami ve~je nastajajo na mestih mikrocon, kjer je vsebnost intermetalnih spojin ve~ja pred varjenjem in je vsebnost Fe in Mn, ki sestavljata intermetalne spojine, prav tako ve~ja po varjenju.Rezultati analiz so avtorjem pokazali, da porazdelitev intermetalnih spojin na povr{ini plo~evine vpliva na velikost to~k nastalih med laserskim varjenjem.