Sustainable microwave processing and surface characterization of powdered tungsten reinforced copper metal matrix (Cu-Wx) castings

Abstract

The present work focuses on in-situ melting and casting of powdered copper metal matrix composites using a microwave hybrid heating approach. The composites of copper metal matrix are developed in such a way that the conductivity is least affected and related mechanical properties like flexural strength, tensile strength and hardness can be improved. Present work reports the processing and characterization of tungsten (W) powder reinforcement copper metal composites with weight percentages of W varied from 1%, 3% and 5%. The complete mechanism of interactions of Cu-Wx (x = 1%, 3% and 5% weight of copper powder) based composite powders with microwave heating is explained. The processed composite castings are characterized metallurgically through metallurgical microscope, SEM/EDS and XRD analysis; which reveals even dispersion of W particles in Cu matrix phase with some agglomerations. Some intermetallic formations are observed due to intense heating characteristics of microwaves. Further, mechanical and electrical characterizations of developed castings are carried out through Vicker's microhardness testing and electrical conductivity tests respectively. Addition of reinforced particles in metal matrix leads to an increase in microhardness on the expense of conductivity of composite. The 5% W addition led to 1.5 times increase in microhardness and 18.25% increase in resistivity. The mechanical testing revealed that the 5% W reinforced casting led to ∼22% higher ultimate tensile stress in comparison to pure copper casting. However, there was a significant decrease in ductility of metal matrix composites.