Additive Manufacturing of Lightweight, Fire-Resistant Alloys for Automotive and Aerospace Applications

Abstract

The current review has critically discussed the industrial preparedness of additive manufacturing (AM) in lightweight, fire-resistant alloys, and it is found that its so-called transformative potential is oversold in recent literature. Empirical research has pointed out continuous mechanical unreliability, anisotropy, and defect fragility, which have compromised operational reliability in aerospace and automotive systems. Long-term performance has also been limited by thermal instability, phase heterogeneity, and narrow process windows, and scalability is limited by the fact that post-processing is extensively dependent. Successes in methods like selective laser melting (SLM), electron beam melting (EBM), and directed energy deposition at the laboratory scale have scarcely been translated into reproducible industrial results and residual stresses, irregular microstructures, and quality assurance gaps remain. Alloy progression techniques such as alloy modification and coating on surfaces have not been fully tested to be accepted by regulations as fire resistant, indicating how difficult it has been to balance the mechanical, thermal and safety needs. Regulatory, certification and standardisation have also been found to hinder adoption of the industry, as well as high energy consumption and lifecycle inefficiencies. To mitigate these shortcomings, studies have laid more and more stress on scalable process optimisation, enhanced in-situ monitoring, predictive modelling and stringent life-cycle testing in real conditions. The cooperation of the manufacturers and regulators with the certification bodies has been confirmed to be critical towards creating standard qualification routes. Altogether, AM has shown conditional capability to form lightweight, fire-resistant alloy, but has not yet been able to become industrialised and thus is limited to niche or experimental use instead of providing the radicalising effect that is often advertised.