METHODS AND MODELS OF METALLIC FOAM FABRICATION

摘要: The new science of metallic foams is growing rapidly, in both the scientific research community and industrial applications. Several methods now exist for foaming metals. One these was invented a few years ago at Fraunhofer-Institute Bremen [1, 2]. foam fabricated from metal powder, often aluminium, which mixed with blowing agent that chosen to release gas close melting point metal, e.g. 99.5% aluminium powder 0.5% titanium hydride powder. This mixture processed give dense precursor material then heated up metal. As starts melt, releases expands. resulting cooled freeze structure, solid foam. Figure 1 shows an example such foam, can easily be inside mould, leading possibility reduced post-processing. After expansion phase therefore, foamed liquid undergoes simultaneous drainage cooling. drainage, due gravity, introduces inhomogeneity into generally undesirable view uniform properties required solidified structure. If it continues too long, rupture collapse bubbles will occur. These mechanisms are prevented if freezing process rapid enough. Freezing fronts move inwards through sample, arresting process. In model described below we estimate their velocity relation drainage. currently fabricated. We wish define physical parameters allow other materials this