Review of Sustainable Materials for Automotive Applications

The global automotive industry is undergoing a major transition toward sustainable manufacturing practices in response to increasingly stringent environmental regulations, rising fuel costs, and growing societal emphasis on eco-friendly mobility. Among the various strategies adopted, material innovation plays a pivotal role in reducing vehicle mass, improving fuel efficiency, lowering greenhouse gas emissions, and enhancing recyclability across the product life cycle. This review presents a comprehensive and critical assessment of sustainable materials currently employed and under development for automotive applications. The scope includes bio-based polymers, natural fiber–reinforced polymer composites, recycled and secondary metals, advanced lightweight alloys such as aluminum and magnesium, and emerging smart and multifunctional materials. The mechanical, thermal, and environmental performance of these materials is systematically discussed alongside relevant processing techniques, including injection molding, compression molding, and additive manufacturing. Key advantages—such as weight reduction, renewability, and reduced carbon footprint—are analyzed, along with limitations related to durability, moisture sensitivity, cost, and large-scale manufacturability. Furthermore, life cycle assessment (LCA) methodologies are reviewed to quantify environmental impacts from raw material extraction to end-of-life recycling or disposal. Recent industrial applications and case studies covering automotive interiors, body structures, powertrain components, and energy storage systems are highlighted to demonstrate real-world implementation. Finally, major challenges and future research directions, including material standardization, hybrid material systems, and circular economy integration, are identified. This review aims to serve as a valuable technical reference for students, researchers, and engineers working in the field of sustainable automotive materials.