DEVELOPMENT OF SPARK PLASMA SINTERED ALUMINIUM-NICKEL-COPPER (I) OXIDE METAL MATRIX COMPOSITE

Abstract

Effects of varied contents of copper (I) oxide (Cu2O) and heat treatment on the phases and properties of spark plasma sintered Al-Ni-Cu2O metal matrix composite was studied. The raw materials used were aluminium (Al) powder, nickel (Ni) powder and copper (I) oxide Cu2O powder. Samples were made by blending pre-calculated amounts of raw materials in tubular mixer at a speed of 72 revolutions min-1. The homogenous mixture was sintered at 550°C at a sintering pressure of 40 MPa, heating rate of 50°C min-1 and holding time of 10 min in a graphite die of 20 mm. The phases in the sintered samples were characterized using X-ray diffractometry analysis (XRD). Addition of Cu2O to the samples progressively improved on densification of the samples with increased Cu2O contents. Hardness of the sintered samples was also investigated using Brinell hardness tester. It was observed that the phases which evolved in the sample were influenced by Cu2O content. The presence of 12 % Cu2O in sample C aided development of intermetallic phases within the sample. Presence of 16 % Cu2O in the binary alloy led to development of more intermetallic phases in the sample. Additionally, the hardness and tensile strength notably improved, reaching approximately 107 HB for hardness and 369 MPa for tensile strength particularly with a 12 % copper addition after heat treatment at 260°C. It was concluded that the formation of intermetallic phases within the composite matrix is responsible for the improved hardness and tensile property of the samples.