Mechanical properties, wear and corrosion behavior of copper matrix composites reinforced with steel machining chips

Abstract

The mechanical properties, wear and corrosion behavior of copper matrix composites reinforced with steel machining chips was investigated in this research. Steel machining chips with chip size range of 105μm and below were utilized to develop stir cast copper matrix composites having 5, 7.5 and 10wt% of the chips as reinforcement. Unreinforced copper and 10wt% alumina reinforced copper matrix composites were also prepared for control experimentation. Hardness and tensile properties evaluation, wear test, potentiodynamic polarization corrosion tests, and optical microscopy; were used as basis to characterize the composites produced. The results show that the addition of steel machining chips in copper resulted in significantly low porosity levels in the copper matrix composites compared with the use of alumina as reinforcement. The mechanical properties (hardness and tensile properties) and wear resistance were also observed to improve with the use of the steel machining chips as reinforcement. The corrosion susceptibility in 3.5wt% NaCl solution were observed to be more intense for the unreinforced copper and the alumina reinforced composite grade compared with the steel chips reinforced copper matrix composites. But in 0.3M H2SO4 solution, no consistent corrosion trend was observed although the corrosion resistances of all the composite grades produced were superior to the unreinforced copper. The results demonstrate the capacity of steel machining chips to serve as a reliable cost effective and technically efficient reinforcement material for the development of copper matrix composites.