A novel process to form Al-12 mass % Si bulk material from machined chips using bulk mechanical alloying

A novel process for recycle technology has been developed for materials in form of chip. Machined chips of Al-12 mass%Si alloy were used to demonstrate the effectiveness of the process in producing high strength material with refined microstructure. The process involves Bulk Mechanical Alloying (BMA), preheating and forging. Both primary and eutectic Si particles were refined by repeated extrusion during BMA. The tensile and hardness properties of the materials depend on the Si particle size and the thermal history. The Si particle size is governed by the number of BMA cycle, while the hardness of the alloy depends on the preheating condition. For alloy produced by BMA 500 cycles and preheated at 773 K for 10 min, the tensile strength and Rockwell hardness reaches 431 MPa and 81 HRB respectively. Energy consumption of BMA process is 13.6 kJ/cycle. For BMA 200 cycle, specific energy consumption is 136 MJ/kg.