An investigation on the workability of sintered copper-silicon carbide preforms during cold axial upsetting

摘要

An investigation has been carried out for the determination of the workability behaviour of Cu-SiC composites under two different stress conditions namely plane and tri-axial state. Cylindrical preforms with 95% initial preform density possessing aspect ratio of 0.60 are prepared from copper with various percent content of silicon carbide (up to 20%) metal matrix composites using a die and punch assembly with a 1.0 MN capacity Universal Testing Machine. The sintering operation is carried out in an electric furnace at 850 ± 10°C for a period of one hour in argon inert atmosphere and subsequently they are furnace cooled. Each sintered preform is subjected to an incremental compressive loading under zinc stearate as lubricant. Based on the experimental results, the phenomenon like axial strain (?_z), various stress ratio parameters (namely (ó_m/ó_(eff)) and (?_è/ó_(eff))) and the formability stress index ((3) under two different stress state conditions are systematically analysed considering the barreling effects.