Effect of process parameters on depth of penetration and topography of AZ91 magnesium alloy in abrasive water jet cutting

Abstract

In the present study, the influence of dynamic process parameters such as water pressure, traverse speed and abrasive mass flow rate on depth of penetration and surface topography in high strength AZ91 magnesium alloy were investigated using Abrasive Water Jet (AWJ) cutting technology. Process parameters were varied at 3 levels and influences of each parameter on penetration ability were identified using analysis of variance (ANOVA). Contribution of water pressure and traverse speed on jet penetration found higher compared to abrasive mass flow rate. Profile projector was used to measure depth of penetration. Microstructural features and topography of cut surfaces were examined using Scanning Electron Microscopy (SEM). Micro cutting and ploughing were observed on the top and bottom portion of the cut which were similar to that of modes of deformation in other ductile materials like aluminium and steel. Surface roughness of cut surfaces was measured using Taylor Hobson surface roughness tester. Surface roughness found higher at higher traverse speeds and lower at lower traverse speeds. This study also highlights the suitability of AWJ cutting technology for cutting magnesium and its alloys. Keywords: AZ91 magnesium alloy, Depth of penetration, Profile projector, Topography