Comparative Life Cycle Assessment of Green Sand Casting and Low Pressure Die Casting for the production of self-cleaning AlMg3-TiO2 Metal Matrix Composite

Abstract

The growth in the use of novel materials, as it is the case of the Metal Matrix Composites (MMCs), is producing a positive impact in production processes, allowing to obtain final products with improved functionalities, such as an increase of the strength-to-weight ratio, or enhancement of the mechanical properties of the material, minimizing as well the environmental impacts and production costs without compromising the required technical properties. To determine and compare the environmental impact of different processes employing these materials, this paper provides a comparative analysis of the Life Cycle Assessment (LCA), under ISO 14040:2006 framework and European ILCD guidelines, of two different manufacturing technologies, Green Sand Casting (GSC) and Low Pressure Die Casting (LPDC), for the particular case of a self-cleaning doorknob, produced by an aluminium alloy reinforced with hard TiO2 nanoparticles, that confers special characteristics to the composite, such as an increase of the hardness value and tensile strength, a high wear resistance, a good chemical stability, and antibacterial properties. The results show a slight difference between both technologies in terms of kg CO2 eq. emitted, with just a 3,16 % variation, where GSC emissions are 13,098 kg, whereas 12,684 kg are released from LPDC. In addition, an economic analysis was performed, showing a 17 % cost reduction in case of LPDC. This study presents for the first time a comparative Life Cycle Assessment of GSC and LPDC, when employing new nanocomposite materials, contributing with novel datasets and meaningful insights to improve the state of the art in the field, serving as well as a support for manufacturers in decision making process involving the use of these technologies.