Life Cycle Assessment (LCA) of recycled aluminum Metal Matrix Composites (MMC) reinforced with stainless steel bidirectional continuous fibers

Abstract

Metal Matrix Composite materials (MMC) are usually made by dispersing a reinforcing material embedded and completely continuous in a monolithic material or metal matrix. The reinforcing material can be metal, ceramic or an organic compound that provides the MMC with an increase in stiffness, strength, conductivity, corrosion resistance, thermal properties, wear resistance and fatigue life. Its manufacture requires considerable energy and raw material, since the matrix material must be fused in a furnace. In recent years, the valuation of waste, as well as the reduction of the impact of the product or process on the environment, has forced the use of some material waste for the manufacture of new composite materials. Life cycle assessment (LCA) is a tool that is used to evaluate the consumption of energy and raw materials, and the impact of waste and emissions of a product or process on the environment. This work proposes a comprehensive studio to determine the yield stress, tensile strength and toughness, as well as the LCA of the manufacturing process of a novel composite material that is composed of EN AW 6082 recycled aluminum alloy matrix reinforced with bidirectional continuous fibers of AISI 304 stainless steel. Five wire diameters and wires spacing oriented at 0°were studied. These were: Ø0.32 mm x 1.41 mm, Ø0.5 mm x 1.81 mm; Ø0.6 mm x 2.177 mm; Ø0.75 mm x 2.72 mm and Ø0.8 mm x 2.7828 mm. The results were compared to those of unreinforced EN AW 6082 recycled aluminum matrix without its bidirectional continuous fibers. The combination of wire diameter wire spacing of 0.8 mm x 2.828 mm provided an increase in tensile strength of 136% over than of unreinforced aluminum. Moreover, the combination of Ø0.32 mm x 1.41 mm and Ø0.8 mm x 2.828 mm gave an increase in toughness of 25%, whereas the combination of Ø0.6 mm x 2.177 mm gave an increase in toughness of 175%. Also, some of the environmental impacts of the manufacturing process of the proposed MMC for each of the five diameters and wires spacing studied hardly varied considerably with respect to unreinforced aluminum. The combination of Ø0.8 mm x 2.828 mm is the one that generates the greatest environmental impact, showing an increase of 2.47%, 0.49%, 30.62% and 50.20% for the abiotic depletion, global warming, human toxicity and acidification respectively. From the results obtained from yield stress, tensile strength and toughness, as well as the LCA of the manufacturing process, it can be stated that the novel MMC proposed in this study has a significant load capacity, both static and dynamic, capable of revaluing a metallic waste, while its manufacturing cost is reduced compared to the manufacturing cost of other MMCs.