Parametric optimization and analysis of cavitation erosion behavior of Ni-based + 10WC microwave processed composite clad using Taguchi approach

Abstract

This study aims to develop cavitation erosion-resistant clads on stainless steel (SS-316) using the microwave cladding technique. Ni-based alloy powder (EWAC) was reinforced with tungsten carbide (10% by wt) powder to obtain composite clads. The cladding process was carried out in a domestic microwave applicator of 2.45 GHz frequency with 900 W power. The microstructure, crystal structure (phase identification and quantification), and microhardness of the developed clad were investigated with scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), and Vickers microhardness tester, respectively. It was found that the deposited clad has a uniform thickness of ∼520 μm, and the microstructure mainly consists of equally dispersed and agglomerated carbides in cellular like Ni-Matrix. XRD analysis reveals that the composite clad was composed of various intermetallic, carbide, and oxide phases. The EWAC + 10WC clad (625 ± 81 HV0.3) has a hardness ∼3.5 times higher than the stainless steel substrate (195 ± 15 HV0.3). The cavitation erosion behavior of the SS-316 and EWAC + 10WC clad was examined by using a vibratory cavitation test apparatus. The parametric cavitation erosion testing was conducted according to the Taguchi L9 orthogonal array (OA) to study the effects of variations in amplitude (AMP), immersion depth (ID), and standoff distance (SOD) on mass loss in SS-316 and composite clad. The parametric study results show that SOD was the most influential test parameter, followed by AMP and ID. SOD contributes more than 50% in the mass loss of SS-316 and clad specimens, whereas AMP and ID contribution was around 32%–37% and 7%–11%, respectively. The developed EWAC + 10WC clad performed ∼6.7 times better than the SS-316. Nevertheless, the SS-316 and EWAC + 10WC clad specimens got severely damage in the form of pits, craters, plastic deformation, lip formation, impingement marks, and secondary cracks.