The blade used in the experiment is monolithic PCBN and the binder is A1. Figure 1 shows the energy spectrum of the matrix and the weight percentage of each element in it.
(1) rake face.
At the end of the experiment, the SEM observation of the rake face after tool failure under six parameters shows that the wear morphology of the rake face under each parameter is basically the same, the rake face wear is uniform, no crack is found under high power, and the wear pattern of the corresponding wear area is also consistent, taking a parameter as an example. Figure 2 is the SEM open multi-topography diagram of rake face wear in v=800m/min and f=0.2mm/tooth, and figure 3 is the energy spectrum of the corresponding region of the multi-profile map.
It can be seen from fig. 2 (b) that there is a small amount of white solids in the worn area of the crescent depression. The energy spectrum results of the selected points in figure 2 (d) are as follows: figure 32, spectrogram 33 and figure 34. The spectrogram 32 shows that there are a large number of Fe elements and more C elements, O elements are reduced, and there are a small amount of Si and Cu in the workpiece, which shows that during the cutting process, the chip flows through the crescent depression. A small amount of shoulder cutting will be bonded to the crescent depression, resulting in bond wear. The increase of C and O elements in figure 33 indicates that chemical wear occurred there, and diffusion wear occurred in a small number of workpieces such as Si, Fe and Mm. The spectrogram 34 is consistent with the matrix spectrogram element, but the A1 element decreases, because the bond wear consumes the binder during the cutting process, resulting in abrasive wear on the rake face, and A1 and the Si in the workpiece form SiAlON. Small parallel traces can also be seen in figure 2 (a). In addition, with the increase of O element, the following reactions may have taken place:
It can be seen from figure 2 (c) that there is a small amount of solid adhered to the tip area near the crescent depression, which can be judged to be shoulder-cutting from figure 29, and a certain degree of chemical wear has occurred from spectra 30 and 31. In the area away from the tool tip, such as Fig. 2 (e) and (f), a large amount of solids are attached, almost covering the whole area. From the energy spectrum diagram 31, we can see a large increase in Fe and O, indicating the formation of oxides and adhesion to the tool rake.
At the end of the experiment, the flank after tool failure under six parameters was observed by SEM, and it was found that the wear morphology of the flank was basically the same, the flank wear was uniform, and the wear pattern of the corresponding wear area was also the same. Figure 4 is the flank wear SEM profile of v=1600m/min and f=0.2mm/tooth, and figure 5 is the energy spectrum of the corresponding region of the profile.
Figures 4 (b) and (d) show the morphology of the central area of the flank wear zone, and there is a large area of solids unevenly adhering to the worn surface in the whole wear zone. The energy spectrum analysis of the corresponding area in figure 4 (d) shows that the content of Fe element in the large area attachment band is up to 90%, and there are a small number of Si elements in the workpiece, which indicates that the flank has been bonded during milling. The elements shown in figure 2 are consistent with the matrix elements, the increase of O element indicates that the flank has oxidation wear, BN reacts with O in air to form oxide, and Si element in the workpiece is detected, indicating that diffusion wear has occurred. In addition, a small amount of protruding particles can also be seen on the flank of the cutter. from the increase of Fe and O in figure 3, it can be judged that in the milling process, the temperature of the cutting zone is higher, and oxides are formed by the reaction between Fe and O, which are bonded to the flank of the tool.
There is a large area of attachment in the edge area of the wear zone far away from the cutting edge, which is the oxide formed by Fe and O by energy spectrum analysis. There is a large increase of O element in figure 5, which indicates that oxidation wear has occurred. In figure 6, the elements are similar to the matrix, and there are a small amount of Si, Mg and Fe elements in the workpiece, indicating that diffusion wear occurred.