Effects of nano filler powder during microwave-based joining of SS304 butt joints

Filler powder plays an important role during microwave hybrid heating-based joining process. In this work, nano-size nickel powder has been taken as filler material for preparing SS304-SS304 butt joints. Effects of size of nickel powder on mechanical properties (strength and hardness) of joints have been investigated. Scanning electron microscope tests show that the joints possess uniform microstructure. Energy dispersive spectroscopy tests demonstrated the presence of elements (Chromium, iron, carbon, silicon, manganese, phosphorus) other than filler powder (Nickel) in the joint region thereby confirming complete melting of joint region and also transfer of carbon from graphite separator sheet to joint region during microwave processing. Micro-hardness test results showed that nano-size filler powder-based joints are less prone to surface wear than corresponding micro-size filler powder-based joints. Micro-tensile strength of nano-size nickel powder-based joints is also far better than micro-size filler powder-based joints.