Experimental and numerical investigation of laser forming of closed-cell aluminum foam

Advances in laser forming of metal foam: mechanism, prediction and comparison

“…The process window that is applicable to metal foams is a small subset of the sheet metal process window (with the exception of the scan speed), which is not surprising considering that metal foams can only be bent through a single bending mechanism. Table 1 Typical processing conditions used for sheet metal Yao, 2001b, 2001c;Vollertsen, 1993;Scully, 1987;Masubuchi and Jones, 2000;Edwardson et al, 2005b) and metal foam (Bucher et al, 2016(Bucher et al, , 2017Zhang et al, 2015;Roohi et al, 2015;Guglielmotti et al, 2009;Quadrini et al, 2010Quadrini et al, , 2013Santo et al, 2010Santo et al, , 2012 In general, much higher power levels can be used on sheet metals, for various reasons. First, heat can conduct away from the top surface more easily due to the higher thermal conductivity, and overheating occurs less readily.…”

“…Thus far, successful bending results have only been reported with aluminium-based foams that contain silicon and magnesium as major alloy elements. However, one study attempted laser forming of an aluminium-based alloy with 20 weight percent silicon carbide (SiC), yielding a negative result (Zhang et al, 2015). Bending angles reached barely 1°, and an excessive amount of melting and thermally induced damage was observed.…”

“…The metal foam geometry can be approximated by a solid geometry ('equivalent' model) (Bucher et al, 2016), shown in (a) or modelled explicitly using different levels of geometrical approximation, shown from (b) to (f), (b) and (c) use spherical (Zhang et al, 2015) and Kelvin-cell based (Bucher et al, 2016) unit-cell approaches to model a closed-cell foam, respectively, (d) represents an open-cell model that was also established using a unit-cell approach (Santo et al, 2010), (e) shows a high-density foam model with randomly positioned cavities of different radii (Roohi et al, 2015) and (f) shows a closed-cell foam model that was obtained through a micro-CT scan (Bucher et al, 2016) Equivalent models have the advantage of being extremely simple to implement. A comparatively small number of elements is required, hence computing times are low and multi-pass laser forming experiments are feasible up to large bending angles.…”

“…Due to these unique properties, metal foam excels in many applications such as crash absorbers in cars, as well as structural components in solar power plants and aerospace equipment (Banhart, 2001). Laser forming studies have been performed with different types of metal foams, such as open-cell foams (Quadrini et al, 2010), closed-cell foams (Zhang et al, 2015;Bucher et al, 2016Bucher et al, , 2017, and closed-cell foams with protective skins (Guglielmotti et al, 2009), all reporting that laser forming is capable of bending metal foams up to 45° and beyond. An example for closed-cell aluminium foam is shown in Figure 1.…”

The Influences of Process Parameters on the Preparation of Closed-cell Aluminum foam by Friction Stir Processing

“…Due to the special 3D pore structure of aluminum foam, the sheet metal forming process which is dominated by tensile and shear deformation shows obvious poor formability. Therefore, the first approach is mainly applied to flat components [5][6][7] . For the second process route, whether the hot pressing powder metallurgy technology or the powder composite/cladding rolling technology, essentially speaking, aluminum powder, foaming agent and stabilizer particles are all used to prepare closed-cell aluminum foam.…”