An Advanced Investigation of Polycrystalline Diamond Compact's Degradation Mechanism During Granite Milling

Abstract

The fundamental degradation mechanism of Polycrystalline Diamond Compact (PDC) cutters during granite milling were investigated at various cutting forces and cutting temperature by changing the milling depths and using cooling water or not. The microstructures and compositions of the worn PDC surfaces were characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and Raman Spectroscope. There are mainly two PDC’s degradation mechanisms found. For wet milling test, the PDC cutting temperature grows relatively slow, the thermal expanded cobalt at grain boundaries can squeeze out onto the wear surface, and be scrapped by the sharp granite to scratch the diamond grain, due to the transformation of diamond to graphite. For dry milling test, the PDC cutting temperature dramatically increases, cobalt at grain boundaries in-situ thermal expanse do and cause the huge thermal stresses, resulting in diamond transgrainular cracking and spalling out.

Keywords: Polycrystalline diamond, Abrasion resistance, Wear mechanism, Granite milling