Effects of Microstrutures and Machining Conditions on Surface Roughness of WC-Co Cemented Carbides Machined by Focused Ion Beam
Hiroyuki HOSOKAWA, Koji SHIMOJIMA and Mamoru MABUCHI
Abstract:The WC-Co cemented carbides with the WC grain sizes of 0.4-4.5ƒÊm and the Co contents of 10-15% were machined by focused 30 keV Ga+ ion beam (FIB) at doses of 5.0~1016`2.5~1018 ions/cm2 and their surface roughness was investigated by atomic force microscope (AFM), where FIB machining was carried out by scanning the nominal spot sizes of 100 and 300nm, the beam overlap of 37.5, 50 and 67% and the pixel dwell time of 100 and 227ƒÊs. Experimental results on effects of microstructure on the surface roughness showed that the decrease in WC grain size and averaged phase width of Co is required to reduce the surface irregularities for the FIB micro-machining of WC-Co cemented carbides. Moreover, it was revealed from the viewpoint of effects of machining conditions on the surface morphology that small surface irregularities is obtained by FIB machining with larger beam diameter, larger overlap and shorter dwell time. Key Words:Focused ion beam, Cemented carbide, WC grain size, Co phase, Machining conditions, Beam diameter, Overlap, Dwell time