Assessment of recycled aluminum alloy sourcing in automotive manufacturing: a case study

Thesis Abstract

The automotive sector faces mounting pressures to reduce material costs and environmental impact, prompting a shift toward recycled aluminum alloys; however, traceability, quality consistency, and supply chain integration remain critical barriers in mainstream production. This study investigates the sourcing of recycled aluminum alloys within a mid-size automotive manufacturer, with an emphasis on material specification alignment, supplier qualification, and lifecycle cost implications in a real-world setting. The aim is to evaluate how recycled aluminum can meet the performance, safety, and processability requirements of high-volume vehicle production while delivering demonstrable economic and environmental benefits. Specific objectives are (1) to characterize current recycling streams, material attributes, and process scrap flows across die-casting and body-in-white operations; (2) to assess supplier qualification practices, certification schemes, and traceability mechanisms; (3) to quantify the impact of recycled alloy content on mechanical properties, corrosion resistance, and joining performance using targeted testing; (4) to model total cost of ownership and life cycle environmental impact under different recycling integration scenarios; (5) to identify governance, risk, and data interoperability requirements to enable scale-up. The research adopts a mixed-methods design grounded in the Resource-Based View and the Theory of Constraints to capture both quantitative performance metrics and qualitative supply-chain dynamics. The population comprises 14 tier-one suppliers, 7 die-casting partners, and 3 internal material engineering teams within the case organization, with a purposive sampling of 25 key production batches representing varied alloy compositions and scrap-to-consumable rates. Data collection employs (i) material characterization using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and tensile testing per ISO 6892 standards; (ii) process capability analysis (Cp, Cpk) for recycled content substituting conventional alloys; (iii) supplier audits, certification reviews, and traceability data extraction from SAP ERP and supplier portals; and (iv) semi-structured interviews with 12 engineers and procurement managers, analyzed via thematic analysis to extract governance and risk perceptions. Validity and reliability are ensured through triangulation across material test results, supplier documentation, and interview insights; instrument reliability is assessed using Cronbach’s alpha for survey-derived items, and measurement uncertainty is quantified for mechanical testing. Data analysis integrates regression modeling to relate recycled content percentage to mechanical performance and joinability outcomes, ANOVA to test differences across alloy families, and a multi-criteria decision analysis (MCDA) to evaluate total cost of ownership under four recycling integration scenarios. A conceptual model links material attribute streams, supplier qualification, process capabilities, and life-cycle outcomes. Expected findings indicate that recycled content up to 60% in specific Al-Si alloys can maintain equivalent tensile strength and formability with marginal changes in corrosion resistance when proper homogenization and QC controls are applied; however, variability in impurity profiles and oxide film stability necessitates robust traceability and supplier collaboration. The study anticipates that disciplined supplier qualification, integrated data platforms, and tighter process controls can reduce total material costs by 6–12% and lower embodied energy by 8–15% per vehicle, relative to baseline virgin alloy configurations. The contribution to knowledge lies in an empirical, integrative framework for evaluating recycled aluminum sourcing within automotive manufacturing, bridging material science, operations management, and supply-chain governance, and offering a transferable model for other high-volume metal industries seeking sustainable, cost-effective material strategies. The principal conclusion posits that strategic harnessing of recycled aluminum alloys is feasible for mass production when reinforced by rigorous traceability, standardized QC protocols, and collaborative supplier ecosystems; policy and practice recommendations include implementing a unified material data dictionary, expanding supplier development programs, and pilot-testing recycled-content configurations on low-volume platforms before full-scale rollout.