D Jianxin et al./ International Journal of Machine Tools Manufacture 45(2005)1393-1401 BW20 V=lOOm/min ABW3 Fig 4. Flank wear of Al,,TiB,/SiCw ceramic tools with different TiB Cutting time(min onditions: V=100 m/ min, p o Inconel718 nickel-based alloys(test nd sic Fig. 6. Crater wear of AB W20 ceramic tool at various cutting speeds when The wear by abrasion is usually due to crack development plastically deformed and marks are clearly evident on the and intersection caused by wear particles acting as small rake wear surfaces ndenters on the tool face. Fig. 7(a) shows the SEM Fig 9 shows the cutting temperatures of AB W20 ceramic micrograph of the tool wear profile of ABW20 ceramic tool tool as a function of cutting speeds when machining at a cutting speed of 80 m/min. It appears that both the rake Inconel718 nickel-based alloys. It was found that the conditions. The SEM micrograph of the flank wear track at cutting speeds. The cutting temperature is higher than higher magnification is illustrated in Fig. 7(d). Ridges and 800C when the cutting speed is above m/min,and mechanical plowing grooves are clearly evident on the flank 1109C up to cutting speed of 120 m/min. The increases in wear surfaces, and it is indicative of typical abrasive wear. cutting temperature at higher speeds may cause work piece The probability of finding such features on the flank wear materials pressure weld onto the tool rake face [21] surface is significantly greater Subsequent random plucking of the welded materials In many cases, the abrasive action may also be attributed removes aggregates of the tool particles, which accelerate special features of the flowing chip, which is character- the tool wear. Pressure welding of the work piece material is ized by a serrated profile along its edges(see Fig. 8). possible because the interfacial temperature between This type of serrated chips abrades the tool rake face and the tool and work piece at high-speed conditions falls in creates scars in the rake wear surface. High stresse range of the melting point of the Inconel718 nickel-based generated at the tool-chip interface during machining may alloys. also cause plastically deformed grooves and ridges on rake The SEM micrographs in Fig. 10 were taken from the wear faces. The SEM micrograph of the crater wear track at track of rake face of AB W20 ceramic cutting tool at cutting higher magnification is shown in Fig. 7(b). Abrasion peed of 100 and 120 m/min. The wear track clearly shows lot of adhering materials smeared on the rake face. The adhered work piece particles often remain attached to the tool surface. Adhesive wear of cutting tools involves the mechanism in which individual grains or their small aggregates are pulledout of the tool surface and are carried away at the underside of the chip or torn away by the adherent work piece. Weaker interface bonding between different ceramic phases can increase the severity of adhesion wear. Diffusion wear involves element diffusion and chemical reaction between the work piece and the ceramic tool, and -V=150m/min the process is activated by high-temperatures and is H V=loOm/min observed mainly at the tool-chip interface. This type wear is more pronounced at high cutting speeds or when there is a high-temperature at the tool-chip interface, and is Cutting time (min) accelerated by a high chemical affinity between the work piece and the tool. At high cutting speed, the temperature at 5. Flank wear of ABW20 ceramic tool at various cutting speeds when the tool-chip interface increases and the transfer of material machining Inconel718 nickel-based alloys. between the work piece material and the tool occursThe wear by abrasion is usually due to crack development and intersection caused by wear particles acting as small indenters on the tool face. Fig. 7(a) shows the SEM micrograph of the tool wear profile of ABW20 ceramic tool at a cutting speed of 80 m/min. It appears that both the rake face and flank face were severely worn under these test conditions. The SEM micrograph of the flank wear track at higher magnification is illustrated in Fig. 7(d). Ridges and mechanical plowing grooves are clearly evident on the flank wear surfaces, and it is indicative of typical abrasive wear. The probability of finding such features on the flank wear surface is significantly greater. In many cases, the abrasive action may also be attributed to special features of the flowing chip, which is character￾ized by a serrated profile along its edges (see Fig. 8). This type of serrated chips abrades the tool rake face and creates scars in the rake wear surface. High stresses generated at the tool–chip interface during machining may also cause plastically deformed grooves and ridges on rake faces. The SEM micrograph of the crater wear track at higher magnification is shown in Fig. 7(b). Abrasion plastically deformed and marks are clearly evident on the rake wear surfaces. Fig. 9 shows the cutting temperatures of ABW20 ceramic tool as a function of cutting speeds when machining Inconel718 nickel-based alloys. It was found that the cutting temperature increased exponentially with increasing cutting speeds. The cutting temperature is higher than 800 8C when the cutting speed is above 80 m/min, and 1109 8C up to cutting speed of 120 m/min. The increases in cutting temperature at higher speeds may cause work piece materials pressure weld onto the tool rake face [21]. Subsequent random plucking of the welded materials removes aggregates of the tool particles, which accelerate the tool wear. Pressure welding of the work piece material is possible because the interfacial temperature between the tool and work piece at high-speed conditions falls in range of the melting point of the Inconel718 nickel-based alloys. The SEM micrographs in Fig. 10 were taken from the wear track of rake face of ABW20 ceramic cutting tool at cutting speed of 100 and 120 m/min. The wear track clearly shows lots of adhering materials smeared on the rake face. The adhered work piece particles often remain attached to the tool surface. Adhesive wear of cutting tools involves the mechanism in which individual grains or their small aggregates are pulled out of the tool surface and are carried away at the underside of the chip or torn away by the adherent work piece. Weaker interface bonding between different ceramic phases can increase the severity of adhesion wear. Diffusion wear involves element diffusion and chemical reaction between the work piece and the ceramic tool, and the process is activated by high-temperatures and is observed mainly at the tool–chip interface. This type of wear is more pronounced at high cutting speeds or when there is a high-temperature at the tool–chip interface, and is accelerated by a high chemical affinity between the work piece and the tool. At high cutting speed, the temperature at the tool–chip interface increases and the transfer of material between the work piece material and the tool occurs. Fig. 4. Flank wear of Al2O3/TiB2/SiCw ceramic tools with different TiB2 and SiCw content when machining Inconel718 nickel-based alloys (test conditions: VZ100 m/min, apZ0.3 mm, fZ0.15 mm/r). Fig. 5. Flank wear of ABW20 ceramic tool at various cutting speeds when machining Inconel718 nickel-based alloys. Fig. 6. Crater wear of ABW20 ceramic tool at various cutting speeds when machining Inconel718 nickel-based alloys. D. Jianxin et al. / International Journal of Machine Tools & Manufacture 45 (2005) 1393–1401 1397