INVESTIGATING THE IMPACT OF DEPOSITION PRESSURE ON CRN COATING PROPERTIES AND MACHINING PERFORMANCE WITH BUILD UP EDGE FORMATION

Coating properties, including hardness, elastic modulus, roughness, adhesion, and residual stress, significantly impact tool performance and wear patterns in machining.Physical vapor deposition (PVD) coatings offer tailored property combinations for specific applications, adjustable through deposition conditions like N2 gas pressure.This study focuses on customizing CrN coatings to enhance machining, particularly in reducing built-up edge (BUE) formation.Three CrN coatings with varying N2 gas pressures were deposited and characterized using X-ray diffraction (XRD) and nanoindentation testing.These techniques provided insights into the coatings' structural and mechanical properties.The wear performance of these coatings was evaluated through a series of machining tests involving the finish turning of TiAl6V4 titanium alloy.Tool life studies were conducted to assess the coatings' performance under machining conditions, while 3D wear volume measurements were executed to quantify the degree of tool wear and observe its progression.The results demonstrated that tailored CrN coatings with specific properties, such as a high elastic modulus, low H/E ratio and high plasticity index, were highly effective in reducing problems associated with sticking and built-up edge (BUE) formation.