Preparation And Properties Of AlCrTiSiN Coatings For Cutting Gray Gast Iron Engine Housings

In this paper,the optimized tool coating was designed for the machining of gray cast iron engine housings.AlCrTiSi N nanocomposite coatings with different transition layer structures?marked as G1?G2?G3?and thicknesses?marked as T1?T2?T3?were deposited on the surface of cemented carbide samples,milling cutters and driller by using multi-arc ion plating technology.The microstructure,morphology,stress,adhesion strength,hardness,and friction and wear properties of AlCrTiSiN coatings with different transition layer structures and thicknesses were studied in detail using X-ray diffraction,scanning electron microscopy,energy dispersive spectroscopy,scratch test,and friction and wear tester.At the same time,the milling and drilling performances of the coatings were studied,and the cutting mechanism was discussed in detail.The results were summarized as follows.?1?Cr and Al is present as?Cr,Al?N solid solution in the AlCrTiSiN coating with different transition layer structures and thickness.Ti and Si mainly exist in TiN phase and amorphous Si₃N₄ phase,respectively.?2?Among the AlCrTiSiN coatings with different transition layer structures,the G3coating with the most gentle transition has high adhesion strength and anti-wear properties;The lowest residual compressive stress of-3.8 GPa is observed in G3 coating.?3?Among the AlCrTiSiN coatings with different thicknesseses,the thinner T1?2.2?m?and T2?3.6?m?coatings have higher adhesion strength,no cracks and spalling around the indentation are found,and the residual stress of the coatings increases with thickness.The wear rate of T2 and T3?4.7?m?coatings are small,and the wear surface is smooth.?4?For AlCrTiSiN coatings with different transition layer structures,the milling and drilling lifes of the G3 coated tools are the highest.For the AlCrTiSiN coatings with different thicknesses,the T3 coating shows the best milling and drilling performances,which is more suitable for tool cutting.The wear mechanism of coated cutters is mainly characterized by spalling failure,abrasive wear and adhesive wear.