Laser processing of metal foam
Some important properties of the metal foams that make them attractive materials for various purposes are their excellent stiffness to weight ratio (light-weight structure), ability to take up strain by crushing at controlled pressure (energy and impact absorption), order of magnitude higher damping capacity as compared to the solids (mechanical damping), higher natural flexural vibration frequencies (vibration control), reasonable sound absorbing capacity accompanied by durability and fire resistance (acoustic absorption), and, high area of contact accompanied by high thermal conductivity (heat exchanger). Often foam is joined or connected to cover sheets of the same metal and the whole part together is called a foam sandwich. Among all the metal foams aluminium metal foam has found the widest and diverse application. This article covers important recent literature on laser processing viz. laser forming, laser welding, laser cutting and laser additive manufacturing of metal foams. Prior to this, a link is established between foam/foam sandwich and laser processing techniques stating the limitations of other relatively more conventional processing techniques. Future research direction regarding different laser processing techniques using metal foams has also been outlined.