Functionalised polycrystalline boron nitride materials via laser surface engineering

Polycrystalline boron nitride cutting tools are widely used for hard-part steel turning due to their high wear resistance and long durability, however microstructurally different composites suited machining applications. For example, low cBN content grades (cBN<50%) in continuous lightly interrupted of automotive steels the valve seat alloys; while (cBN>85%) designed provide excellent abrasion chip therefore suitable grey hard cast irons, hardened milling alloys where a longer tool life is required. In this paper, using nanosecond fibre laser (1064-nm wavelength), surface engineering polycrystalline two materials (50% 90% content) proposed functionalise mechanical properties enable extend applicability specific grade variety The materials’ response fluences, feed speeds pulse durations was investigated characterised through combination 3D white light interferometry, scanning electron microscopy (SEM) micro-hardness measurements. metrological data (Sa, Spk, Sku Sq) samples were measured prior post-process an indication change properties. Fractures between grains binder reduced integrity highlighted by SEM analyses thermal stress caused difference thermodynamic binder. Increased frequency energy density local heating corroborated larger Sa, Spk Sq values but lower values. Micro-hardness measurements revealed up 20% increased hardness 10% decreased root mean square height (Sq) with speed per pulse. Improvements reductions roughness both PCBN observed, suggesting that use could lead improvements performance application industry beyond conventional grade.