Forging of 2124/SiCp composite: Preliminary studies of the effects on microstructure and strength

Forging behaviour of 2124 aluminium alloy containing 26vol.% of SiC particles (average size 3μm) was investigated by means of room and elevated temperature tensile tests (range of temperature 20-350°C). The results obtained were utilized to define the forging parameters (deformation ratio 3.5:1, strain rate 0.14s-1, sample temperature during the hot deformation process ranging from 440 to 340°C). Microstructure of as-fabricated and forged specimens was investigated. Microfractographic examinations were executed on the tensile fracture surfaces, obtained by testing the composite both at room and high temperature, in order to investigate the mechanism controlling the fracture process. The material exhibited excellent forgeability and after forging the tested composite was found to be crack free. This feature is very likely due to the size of the reinforcing SiC particles, smaller than those generally used for conventional metal/ceramic composite processing. Furthermore, forging resulted in an increase of both tensile strength and ductility with respect to the as-fabricated condition. The performing of T4 treatment on forged specimens highly increased yield and tensile strength, the ductility still remaining similar to that of HIP billets.