Materials and Technologies for Lightweighting of Structural Parts for Automotive Applications: A Review

Reducing the weight of automotive components is one of the most achievable solutions for lowering the transport carbon footprint. This is the reason for the rapid increase over the last few years in the replacement of conventional alloys (i.e., steel and cast iron) with low-density materials (i.e., aluminum alloys, composites) and in the redesign of components shape in order to remove the unnecessary material (e.g., related to the introduction of additive manufacturing or high-strength materials). Despite this general trend, the use of higher-density metals and massive geometries is still predominant in the production of structural components, especially for heavy vehicles and safety-relevant parts. Aim of the present review is to summarize how this current situation can be overcome. The analysis started with an investigation about the materials that can be used for the production of structural parts, the potential reduction of the component weight and its costs. The scenarios analyzed foreseen by 2030 an improved weight reduction combined with additional cost. Both the parameters increased when moving from medium/small vehicles to luxury vehicles (from -18% to -35% weight and from €3 to €8-10 per kg saved, respectively) as a direct consequence of an increased usage of lighter materials. Then, the research reports some relevant actual applications, which succeeded in the weight reduction of these kind of components. The identified materials and technologies discussed were: advanced high-strength steel, carbon fiber-reinforced polymer, aluminum, additive manufacturing technologies, and alternative joining techniques.