Development and characterization of microwave processed cast iron joint

Abstract

The feasibility of joining cast iron through novel microwave heating using susceptor (i.e. microwave hybrid heating), is carried out in present work. The joints were developed in domestic microwave applicator at 2.45 GHz frequency and 900 W. Nickel based powder slurry was placed between the faying surfaces for obtaining the joint. The detailed mechanism of joining through microwaves has been explained by using suitable illustrations. The microwave processed joint was characterized by using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction for microstructure analysis and study of developed inter-metallic phases. Results revealed that uniform and dense joint of 0.5 mm thickness were obtained. Obtained joints revealed metallurgical bonding of nickel powder with faying surfaces of base metal. This metallurgical bonding resulted into wavy interface and this was due to dilution of the base metal along the joint region. The EDS analysis confirms the uniform distribution of elements in the joint region and SEM results revealed that some porosity (in the range of 1.5–1.88%) was observed in the joint region. Tensile strength of microwave joined cast iron was ∼90% of the base metal strength. This was due to the development of high strength intermetallics and presence of nickel metal in the joint region. Microhardness at joint region was 201.7 ± 18 HV and 315 ± 10 HV along HAZ, whereas microhardness of bulk cast iron was 184 ± 4 HV. Microwave processed samples fractured along the HAZ region.