Green recycling of aluminium alloys: Microwave-based solid-state technique for composite sheet fabrication

Recycling of aluminium chips is challenging due to the presence of surface oxide layers, high energy consumption, long processing times, low recovery, and substandard product quality. Despite having a potential of 95% energy and cost-saving, reduced emissions and solid waste, only 30-35% are being recycled currently due to the lack of energy-efficient, economical, and eco-friendly technologies. Therefore, the present study explores a microwave-based solid-state recycling technique to convert aluminium alloy chips into composite sheets. The process offers a cost-effective, energy-efficient, and environmentally friendly alternative to conventional recycling methods. It is applicable to both age-hardenable and non-age-hardenable aluminium alloys. By using microwave energy to form recycled composite compacts, the method achieves a 35–38% increase in energy efficiency compared to traditional approaches. Notably, for age-hardenable alloys, the process enhances productivity by leveraging strain-induced precipitation, which significantly reduces post-ageing time by 60–75%. This innovative approach promotes sustainable manufacturing while delivering high-performance recycled materials.

Abhishek Maurya is a Ph.D. scholar in the Department of Mechanical Engineering at IIT Madras. He completed his master’s degree in Manufacturing Engineering from the same institute and holds a bachelor's degree in Mechanical Engineering from IIT Patna. His research focuses on advanced manufacturing techniques, with a particular interest in microwave-based material processing, advanced machining, and microforming.