ADVANCED MATERIALS & PROCESSES | MARCH 2026 21 of recycled pellets in extrusion-based AM, can lower material costs and reduce reliance on virgin raw materials. These benefits are especially pronounced in high-value alloys, where feedstock cost can represent a significant fraction of total part cost. As illustrated in Fig. 3, the largest difference between pathways occurs in energy consumption and GHG emissions, reflecting the strong dominance of feedstock production in the environmental impact of conventional AM supply chains. For metals like aluminum, the “virgin AM feedstock” route carries the burden of primary metal production and additional energy for atomization and classification when powder is required, driving energy demand to the order of ~10² MJ/kg (e.g., ~194 MJ/kg is used here as an average representative value). In contrast, the recycling/reprocessing route reduces this substantially (e.g., ~7.5 MJ/kg for remelting/casting in the baseline comparison), and the solid-state upcycling route can generate further lower values since remelting is eliminated (e.g., ~0.01 MJ/kg for manual compaction of chips into feedstock). A similar hierarchy is seen for GHG emissions as well, although absolute values remain sensitive to system boundary definitions and electricity (for example, recycled aluminum is often reported as process emissions only, while primary aluminum values are typically cradleto-gate and much larger). The cost and material utilization trends shown in the figure reinforce that upcycling can be advantageous beyond sustainability. In this dataset, the solid-state upcycling route achieves both higher material utilization (lower material loss) and lower production/ processing costs than the recycling via remelting route. This outcome reflects the fact that remelting-based recycling can incur additional operational burdens, such as melt losses, furnace energy, and associated handling, whereas chip-based compaction and solid-state processing can avoid melt-related oxidation and dross while retaining more material value. At the same time, it is important to note that the economic advantage of upcycling remains boundary- and implementation-dependent, meaning chip cleaning, sorting, densification, and quality assurance can raise costs if performed in low-throughput or poorly integrated workflows. Consequently, upcycling will most likely continue to remain cost-competitive when implemented near the point of waste generation by minimizing intermediate handling and achieving repeatable feedstock quality at scale. Together, these trends suggest that upcycling can deliver an unusual combination of lower energy consumption, emissions, material loss, and processing costs than remelting-based recycling. Overall, the growing body of work in this area suggests that upcycling is most impactful when it is tightly integrated into manufacturing workflows, minimizes intermediate processing, and targets applications where material cost and embodied energy are critical drivers. INDUSTRIAL OUTLOOK AND FUTURE DIRECTIONS Interest in upcycled feedstocks for additive manufacturing is rapidly expanding as industries face increasing pressure to reduce cost, improve supply-chain resilience, and meet sustainability targets. While widespread commercial adoption is still emerging, several sectors are actively spearheading the development and early deployment of upcycling-enabled AM workflows. The aerospace and defense industries have been among the earliest adopters, driven by high material costs, stringent sustainability goals, and the availability of well-characterized machining scrap from qualified alloys. Solid-state AM platforms, including AFSD, are being explored for both structural fabrication and repair applications using upcycled feedstock, particularly where closed-loop manufacturing can be implemented. Similarly, energy-sector stakeholders are investigating upcycling strategies to support large-scale components, tooling, and repair operations, where material efficiency and throughput are key considerations. Cold spray repair and additive build-up is increasingly being adopted in the defense sector due to its ability to restore components without melting and to support field- deployable repair workflows. In conjunction, polymer-based extrusion AM has seen growing industrial use of recycled and post-consumer materials, especially in tooling, construction, and consumer-product applications. These efforts benefit from relatively mature recycling infrastructure Fig. 3 — Qualitative comparison of key environmental and economic indicators for three feedstock pathways: virgin AM feedstock, recycled/reprocessed feedstock, and upcycled feedstock (solid-state route). Note: All values are normalized with respect to virgin AM feedstock = 100% within each category to illustrate the relative impact.
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