In the laser treatment of a workpiece (9), e.g. for surface hardening, melting, alloying, cladding, welding or cutting, the adverse effect of reflectivity of the surface, when a pure, monochromatic laser (6) is used, is remedied by the simultaneous application of a relatively shorter wavelength beam (1). The two beams (1)(5) may be combined by a beam coupler (4) or may reach the workpiece (9) by separate optical paths (not shown). The shorter wavelength beam (1) improves the coupling efficiency of the higher- powered laser beam (5).

Laser Material Processing

Today, hybrid manufacturing technology has drawn significant interests from both academia and industry due to the capability to make products in a more efficient and productive way. Although there is no specific consensus on the definition of the term ‘hybrid processes’, researchers have explored a number of approaches to combine different manufacturing processes with the similar objectives of improving surface integrity, increasing material removal rate, reducing tool wear, reducing production time and extending application areas. Thus, hybrid processes open up new opportunities and applications for manufacturing various components which are not able to be produced economically by processes on their own. This review paper starts with the classification of current manufacturing processes based on processes being defined as additive, subtractive, transformative, joining and dividing. Definitions of hybrid processes from other researchers in the literature are then introduced. The major part of this paper reviews existing hybrid processes reported over the past two decades. Finally, this paper attempts to propose possible definitions of hybrid processes along with the authors’ classification, followed by discussion of their developments, limitations and future research needs.

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A review of hybrid manufacturing processes – state of the art and future perspectives

Hybrid welding, using the combination of a laser and an electrical arc, is designed to overcome problems commonly encountered during either laser or arc welding such as cracking, brittle phase formation and porosity. When placed in close contact with each other, the two heat sources interact in such a way as to produce a single high intensity energy source. This synergistic interaction of the two heat sources has been shown to alleviate problems commonly encountered in each individual welding process. Hybrid welding allows increased gap tolerances, as compared to laser welding, while retaining the high weld speed and penetration necessary for the efficient welding of thicker workpieces. A number of simultaneously occurring physical processes have been identified as contributing to these unique properties obtained during hybrid welding. However, the physical understanding of these interactions is still evolving. This review critically analyses the recent advances in the fundamental understa...

Problems and issues in laser-arc hybrid welding

Numerical and experimental study of thermally induced residual stress in the hybrid laser–GMA welding process

Effects of heat input on microstructure and tensile properties of laser welded magnesium alloy AZ31

One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At the same time, it identifies both the mechanism of pore formation and a remedy for this problem. The experimental results indicate that lacking of shielding gas for laser beam is the dominant cause of macroporosity formation during the hybrid of laser-TIG welding of magnesium Alloys AZ31B plate, and hydrogen is not main cause to form large pores. A favorable weld without porosity can be obtained by appending lateral shielding gas for laser beam.

Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31B—mechanism and remedy

This paper presents the results of recent investigations on the overlap weldability of magnesium alloy AZ31B sheets by laser-arc hybrid welding process The effects of key welding parameters such as welding speed, defocusing distance, and laser-to-arc distance on overlap weldability of magnesium alloys sheets were analyzed, as well as the microstructure and properties of hybrid lap-welded joint The results showed that sound overlap-welded joints of magnesium alloy AZ31B sheets without defects can be obtained Among the welding parameters, defocusing distance and laser-to-arc distance were key factors to affect the penetration depth and bead shape It also found that the cross-section of hybrid overlap-welded joint appears a “thumb pin” shape due to the characteristics of laser-arc hybrid welding Hybrid overlap-welded joints can be divided into two parts: one was the zone of laser acting alone, while the other was the zone of laser and arc cooperation Besides, it was concluded that the tensile shear strength of AZ31B overlap-welded by laser-arc hybrid welding was 80% comparable to those of base metal, and the corrosion resistance of weld bead was equivalent to that of base metal in 5 mol% NaCl solution

Overlap welding of magnesium AZ31B sheets using laser-arc hybrid process

Immiscible Mg/steel was welded by laser–tungsten inert gas (TIG) butt fusion welding method with AZ61 filler wires. A better joint was obtained by optimizing the process parameters. The tensile strength of Mg/steel joints was improved with the increase of laser power before the weld burn–through. The interface bonding strength reached 238.1 MPa, about 94.5% of AZ31 base metal, and the joint fractured approaching Mg/steel interface. The Mg/steel interface layer was mainly composed of a continuous 50 nm–thick high temperature (HT)–Al11(Mn, Fe)4 intermetallic compound layer and approximately 350 nm–thick α–Fe(Al) solid solution. The orientation relationships (OR) of α–Fe(Al)/HT–Al11(Mn, Fe)4 system and Mg/HT–Al11(Mn, Fe)4 system matched favorable with (011)α–Fe(Al)||(060)HT–Al11(Mn, Fe)4 and [ 1 1 0 ] α–Fe(Al)|| [ 100 ] HT–Al11(Mn, Fe)4, ( 01 1 ¯ 2 ) Mg||(060)HT–Al11(Mn, Fe)4 and [ 10 1 ¯ 0 ] Mg||[100]HT–Al11(Mn, Fe)4, respectively. The growth model of the interface layer along the Mg/steel interface was discussed.

Gang Song

Papers

Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31B—mechanism and remedy

Overlap welding of magnesium AZ31B sheets using laser-arc hybrid process

The mechanical properties and interface bonding mechanism of immiscible Mg/steel by laser–tungsten inert gas welding with filler wire

Effect of laser-GTAW hybrid welding heat input on the performance of Mg/Steel butt joint

Investigation of unequal thickness Mg/steel butt-welded plate by hybrid laser-tungsten inert gas welding with a Ni interlayer