Three types of laser beam oscillating welding were applied on 5A06 aluminum alloy sheets. The microstructure and mechanical properties of the welded joints were characterized. The formation and elimination mechanisms of welding pores during laser beam oscillating welding was investigated. The results showed that laser beam oscillating welding using linear, circular and infinity paths allow to reduce the porosity of the welded joint when compared to the joint produced without beam without oscillation. Among the three oscillating paths, the infinity mode was the best in terms of decreasing the porosity in the weld and increasing the tensile strength. The decrease in porosity of the fusion zone was associated with the weld shape and the decrease of the depth-to-width ratio of the weld due to the oscillation of the heat source. Laser beam oscillating welding applied to aluminum alloys can be of significant interest to industry to decrease porosity problems typically encountered during laser welding of these materials.

Laser beam oscillating welding of 5A06 aluminum alloys: Microstructure, porosity and mechanical properties

Joining aluminum to steel can lighten the weight of components in the automobile and other industries, which can reduce fuel consumption and harmful gas emissions to protect the environment. However, the differences of thermal, physical, and chemical properties between aluminum and steel bring a series of problems in laser welding. The main problems are how to control the thickness of the intermetallic compound layer and reduce or avoid the generation of pores, cracks, and thermal stresses which severely limit the mechanical properties of welded joints. Laser fusion-brazing technology utilizes the precise control of heat input with or without filler to partially melt the low melting temperature aluminum base material and promote wetting on the high melting temperature steel base material in order to achieve sound metallurgical by combining the advantages of fusion welding and brazing. Different forms of laser beam welding including single beam laser welding, dual-beam laser welding, and laser arc hybrid fusion-brazing welding are reviewed.

Laser welding dissimilar materials of aluminum to steel: an overview

Reduction of pores by means of laser beam oscillation during remote welding of AlMgSi

A study on laser beam oscillating welding characteristics for the 5083 aluminum alloy: Morphology, microstructure and mechanical properties

In recent years, there is an increased in used of titanium alloys for some parts of mass-produced automobiles and aerospace. However, titanium alloys are characterized by difficult machinability, high melting temperature, high strength, low thermal conductivity, and high reactivity to oxygen, which overshadowed conventional manufacturing processes. To this end, there is a pressing need for more efficient technologies for the manufacture of low-cost titanium structures. Over the years, several joining techniques have been considered for fabrication of titanium alloys. Nevertheless, laser beam welding presents a viable option for welding of titanium due its versatility, high specific heat input, and flexibility. To date, under optimum processing conditions, the strength of the laser-welded titanium alloys can be close to the original material; however, there are still some processing problems such as lower elongation and corrosion resistance coupled with inferior fatigue properties. In this document, the laser beam welding of similar and dissimilar titanium alloys is reviewed, focusing on the influence of the processing parameters, microstructure-property relationship, metallurgical defects, and possible remedies.

A review on laser beam welding of titanium alloys

Effect of beam oscillating pattern on weld characterization of laser welding of AA6061-T6 aluminum alloy

Laser–cold metal transfer arc hybrid welding of 6061 Al alloy and AISI304 stainless steel (304SS) was carried out. Bead morphologies and intermetallic compound (IMC) layer characterizations of the joints were studied in detail. The optimal parameter range for accepted bead appearances (OPRBA) without surface and interface defects was obtained, and the growth mechanism of the IMC layer was summarized. The results showed that the nonuniformity in the thickness and shape along the fusion zone/304SS interface from the top surface to the bottom increases with increasing heat input and is more sensitive to laser power because the interface temperature is dominated by a high-temperature laser keyhole throughout the molten pool. As the welding parameters are within the OPRBA and the heat input is within the range of 80–110 J/mm, the joints are stronger than 130 MPa and the corresponding IMC layer thickness is at the range of 3–6.5 μm. The kinetic analysis showed that a controlling interface temperature no more than 1,120 °C may limit the growth of the IMC layer.

Parameter optimization and mechanism of laser–arc hybrid welding of dissimilar Al alloy and stainless steel

Study of porosity suppression in oscillating laser-MIG hybrid welding of AA6082 aluminum alloy

Laser-arc hybrid welding with Cu3Si filler wire was employed to join dissimilar Ti6Al4V titanium alloy and AISI316 stainless steel (316SS). The effects of welding parameters on bead shape, microstructure, mechanical properties, and fracture behavior were investigated in detail. The results show that cross-weld tensile strength of the joints is up to 212 MPa. In the joint, obvious nonuniformity of the microstructure is found in the fusion zone (FZ) and at the interfaces from the top to the bottom, which could be improved by increasing heat input. For the homogeneous joint, the FZ is characterized by Fe67−x
 Si
 x
 Ti33 dendrites spreading on α-Cu matrix, and the two interfaces of 316SS/FZ and FZ/Ti6Al4V are characterized by a bamboo-like 316SS layer and a CuTi2 layer, respectively. All the tensile samples fractured in the hardest CuTi2 layer at Ti6Al4V side of the joints. The fracture surface is characterized by river pattern revealing brittle cleavage fracture. The bead formation mechanisms were discussed according to the melt flow and the thermodynamic calculation.

Lei Wang

Papers

Effect of beam oscillating pattern on weld characterization of laser welding of AA6061-T6 aluminum alloy

Parameter optimization and mechanism of laser–arc hybrid welding of dissimilar Al alloy and stainless steel

Study of porosity suppression in oscillating laser-MIG hybrid welding of AA6082 aluminum alloy

Laser-Arc Hybrid Welding of Dissimilar Titanium Alloy and Stainless Steel Using Copper Wire

A pathway to mitigate macrosegregation of laser-arc hybrid Al-Si welds through beam oscillation