Aluminum Foam-Filled Steel Tube Fabricated from Aluminum Burrs of Die-Castings by Friction Stir Back Extrusion

Production of Closed-Cell Foams out of Aluminum Chip Waste: Mathematical Modeling and Optimization

The main aim of this research is to mathematically describe the influence of the processing parameters of metal foam production from machining chip waste. Using this method, metal foams were produced without a remelting step, which should be both economically and environmentally effective. Firstly, expensive metal powders were replaced with waste in the form of machining chips. Secondly, machining chip waste was recycled without any significant material losses, which usually occurs during conventional recycling (using the melting process). To describe the innovative process and to relate metal foam properties to foaming temperature, the blowing agent weight percentage, foam density (controlled by foaming height), response surface methodology, and the design of experiments were used. The quality of the produced metal foams was evaluated by determination of density, yield strength, compression strength, plateau stress, energy absorption, pore perimeter, and pore inhomogeneity for specimens obtained following the experimental plan. It was proven that pore inhomogeneity increased in the range from 1.41 to 4.81 mm with a higher temperature and the addition of a foaming agent. However, higher energy absorption and yield strength were obtained with a higher temperature but a lower percentage of TiH2. Despite the production from machining chips, pores were homogenous without significant cracks. These kinds of metal foams are comparable to commercial foams made of metal powders.

Brief Review on Experimental and Computational Techniques for Characterization of Cellular Metals

The paper presents a brief review of the main experimental and numerical techniques and standards to investigate and quantify the structural, mechanical, thermal, and acoustic properties of cellular metals. The potential of non-destructive techniques, such as X-ray computed tomography and infrared thermography are also presented.

Automated Continuous Production Line of Parts Made of Metallic Foams

The paper presents an automated continuous production line (7 m × 1.5 m × 1 m) of high-quality metallic foams using a powder metallurgical method. This continuous production line was used to obtain metal foam parts and/or components by heating the foamable precursor material at melting temperatures close to the temperature of the metallic matrix and cooling the formed liquid metallic foam (in liquid state), which then results in a solid closed-cell metallic foam. This automated continuous production line is composed of a continuous foaming furnace, a cooling sector and a robotic system. This installation has enabled a technological breakthrough with many improvements solving some technical problems and eliminating the risks and dangers related to the safety of workers due to the high temperatures involved in this process. The whole process becomes automatic without any need for human intervention.