Semi-finished material and semi-solid forging of SiC particle reinforced al-mg light metal matrix composites – new results on process development and characterisation

Particle reinforced light metal matrix composites (MMC) were manufactured by thermal spraying of semi-finished material (atomisation and co-deposition of reinforcement particles and metal melt), followed by inductive reheating and semi-solid forging. The matrix alloy was Al Mg3, silicon carbide was used as particulate reinforcement. Semi-finished material processing was optimised regarding particle size and temperature distribution during material deposition in order to obtain a suitable microstructure for subsequent semi solid processing. Twin wire electric arc spraying with cored wires was applied, providing the matrix and reinforcement materials at the same time for simultaneous deposition. Process analysis was made by in-flight particle diagnostics. Semi-solid processing ability of the MMC material after thermal spraying was verified by manual deformation testing. Inductive reheating of the particle reinforced material was coupled with fast semi-solid forging by an axial press into a closed, plate-shaped die. Optical and Scanning Electron Microscopy showed some inhomogeneity in the SiC particle distribution. However, mechanical properties from tensile and 4-point bending experiments were encouraging.