Fabrication of Ti-6Al-4V holes using micro-PMEDM via TiC-enhanced deionized water dielectric

Titanium alloy possesses outstanding physical-mechanical properties and biocompatibility, making it highly promising for a wide range of applications. Nevertheless, the precise fabrication of microstructure on titanium alloy continues to present significant challenges. In this paper, a micro powder mixed electrical discharge machining (micro-PMEDM) technique was proposed for the fabrication of micro holes on Ti-6Al-4V surface, employing a uniform suspension of TiC powder (particle size: 1 μm) dispersed in deionized water. The effects of peak current ( I p ), pulse duration ( T on ), pulse interval ( T off ), spindle lifting to in-position machining time ratio ( M , UP: DN), and TiC concentration ( C ) on the single-sided machining gap of microholes were systematically investigated. Results demonstrate that under the matched conditions I p = 0.7 A, T on = 1 μs, T off = 20 μs, M = 2:5, and C = 2 g/L, the single-sided gap was minimized to 29 μm. Compared to machining conducted with pure deionized water, the introduction of TiC suspension considerably mitigated microcrack formation on the cavity surface. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed that machining with deionized water led to a substantial increase in the oxygen concentration on the cavity surface of the fabricated structures, whereas the addition of TiC powder to the deionized water did not significantly increase the carbon content on the machined surface. Finally, utilizing the matched parameters, a micro blind hole pattern spelling GPNU was successfully fabricated, with each hole attaining a depth of approximately 410 μm.