A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing, microstructure, and properties

In recent years, major advances have taken place in our understanding of welding processes and welded materials Because of the complexity of fusion welding processes, solution of many important contemporary problems in fusion welding requires an interdisciplinary approach Current problems and issues in fusion welding are reviewed Solution of these problems, apart from being a contribution to the advancement of science, is also necessary for science-based tailoring of composition, structure, and properties of the welded materials

Physical processes in fusion welding

Advanced materials generally require novel joining techniques. Developments in new materials research should be conducted hand in hand with work on weldability and joining capacity aspects. Sound joint quality for any new material has always been considered a milestone in a research and development scheme for a new material, particularly in terms of widespread applications. Better understanding of the microstructure-mechanical properties relationships of the bonded or welded joints will feed back to the materials development activities both in conventional and new materials areas. The two joining processes diffusion bonding and laser welding are considered in this literature review, since these processes are capable of joining a wide range of materials of interest in the aerospace industry, as well as in many other industrial applications, and offer remarkable advantages over conventional fusion welding processes. Of particular interest is the ability to join the more difficult aerospace alloys wi...

Progress in joining of advanced materials

The automotive industry is facing demands simultaneously to increase its fleet average fuel economy and to reduce the emission of greenhouse gases by its products. In order to meet these new standards, the industry is increasingly aiming to decrease the weight of vehicles through the use of new materials, especially lightweight aluminium alloys. Laser welding is a critical enabling technology in reducing the weight of the body structure through increased use of aluminium and tailor welded blanks. In this review the available research on the laser welding of 5xxx, 6xxx, and some 2xxx series automotive aluminium alloys is critically examined and interpreted from different perspectives. First, the current understanding of the important physical processes occurring during laser welding of these alloys such as energy absorption, fluid flow and heat transfer in the weld pool, and alloying element vaporisation are examined. Second, the structure and properties of these weldments are critically evaluated....

Current issues and problems in laser welding of automotive aluminium alloys

Prospects of laser welding technology in the automotive industry: A review

The effect of Nd:YAG laser welding aluminum alloys 6061, 5456, and 5086 was studied from a perspective of alloying element vaporization, hot cracking susceptibility, and resultant mechanical properties. Both continuous wave and pulsed Nd.YAG laser welds were investigated. It was found that Mg was vaporized during welding, the extent of which was a function of the weld travel speed. Calculations based upon evaporation theory, and assuming a regular solution model, resulted in an estimation of weld pool surface temperatures from 1080 to 1970 K for the continuous wave welds. Pulsed Nd:YAG laser welds were observed to be extremely susceptible to weld metal hot cracking whereas continuous wave Nd:YAG laser welds were crack-free. The hardness of 6061 welds was affected by the Mg vaporization such that base metal strengths could not be achieved by subsequent re-heat treatment to the T6 condition. This loss in hardness was attributed to a reduced ability of the alloy to precipitation harden due to a lower Mg concentration. In the cases of 5456 and 5086, when samples containing welds were processed to the O condition, the weld metal had reduced hardness relative to the base metal. This loss of hardness was also attributed to the loss of Mg in these welds, resulting in reduced solid solution strengthening.

P. W. Fuerschbach

Papers

On the weldability, composition, and hardness of pulsed and continuous Nd:YAG laser welds in aluminum alloys 6061,5456, and 5086