Experimental investigation on micro-drilling properties of Mg-based MMCs reinforced with HAP nanoparticles

Mg-based metal matrix composites (MMCs) reinforced with Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) nanoparticles have been studied as bone substitute materials because of their excellent biocompatibility and biological activity. In this paper, Mg/HAP MMCs with different HAP contents (0.5, 1.0 wt%) were selected and the micro-drilling properties were revealed. Firstly, the chip of MMCs was analyzed. Secondly, the surface roughness of Mg/HAP MMCs under different cutting parameters was studied. The results showed that the surface roughness decreases with the increasing of feedrate and decreases with the increasing of spindle speed, which are contrary to pure Mg. Furthermore, the shapes of burr are all classified as uniform burr, and the burr height increased with the increase of spindle speed and feed. Finally, the size effect of micro-drilling was studied. The minimum cutting thickness per tooth of Mg/HAP MMCs was determined to be 1.0 μm. (paper)