The aluminum alloy with silicon content between 8% and 12% is a transition zone, which can be used not only for ordinary cemented carbide, but also for diamond cutting tools. However, the use of cemented carbide should use PVD (physical coating) method, without aluminum elements, with a smaller film thickness. Because of PVD method and small film thickness, it is possible to keep the cutting edge sharp (otherwise, in order to avoid abnormal growth of the film on the edge, it is necessary to passivate the edge sufficiently, and the cutting aluminum alloy will not be sharp enough), and the aluminum content of the film material may make the film layer of the blade and the workpiece material have affinity and destroy the combination of the film layer and the tool matrix. At present, the superhard coating is mainly composed of aluminum, nitrogen and titanium, which may lead to edge collapse due to a small amount of peeling off of cemented carbide substrate with the coating. Aluminum tube & nbsp;