Dry machining of nodular cast iron using a YAG-reinforced alumina ceramic cutting tool

In this work, an alumina-yttrium aluminum garnet (Al2O3-YAG) cutting tool was developed and characterized aiming application in dry machining of nodular (spheroidal) cast iron. Ceramic powders containing 85 wt.% Al2O3 and 15 wt.% Y3Al5O12(YAG) were homogenized, compacted, and sintered at 1600 °C for 2 h at a heating rate of 5 °C/min. The sintered ceramic presented relative density of 98.3 ± 0.2%. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed α-Al2O3 and YAG as crystal phases, both with equiaxed grains with average sizes of 1–4 μm (Al2O3 phase) and 0.7–1 μm (YAG phase). In addition, this ceramic composite presented Vickers hardness and fracture toughness of 15.2 ± 0.2 GPa and 4.6 ± 0.3 MPa.m1/2, respectively. The dry machining performance of the Al2O3-YAG cutting tool was compared with that of a commercial cemented carbide cutting tool using cutting speed (VC) of 200 and 500 m/min, feed rate (f) of 0.25 and 0.10 mm/rev, and axial depth of cut (ap) of 0.60 mm. The results showed that the best setting for the cemented carbide cutting tool was obtained at VC = 200 m/min and f = 0.25 mm/rev, which produced the best machinability with average surface roughness (Ra) of 3.516 μm, cutting length (LC) of 6000 m, and maximum flank wear (VBmax) of 0.58 mm. For the Al2O3-YAG cutting tool, the best setting was achieved at VC = 500 m/min and f = 0.10 mm/rev, which produced Ra = 0.848 μm, LC = 12,293 m, and VBmax = 0.54 mm.