Original Article

Investigation on microstructural evolution and surface integrity of Ti-6Al-4V alloy machined using WC nanoparticle-enhanced powder-suspended EDM

¹ Department of Mechanical Engineering, Rajalakshmi Institute of Technology, Chennai - 600124, India
² Department of Mechanical Engineering, St. Xavier’s Catholic College of Engineering, Nagercoil - 629003, India
³ Department of Mechanical Engineering, SRM Institute of Science and Technology, Vadapalani, Chennai - 600026, India
⁴ Department of Mechanical Engineering, St. Anne’s College of Engineering and Technology, Panruti - 607106, India
⁵ Department of Mechanical Engineering, Dhanekula Institute of Engineering & Technology, Vijayawada, Andhra Pradesh 521139, India

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 28 June 2025
Accepted: 27 October 2025

Abstract

Ti-6Al-4V paly crucial role in biomedical, automobile, and aerospace sectors; however, its high chemical reactivity and low thermal conductivity poses serious challenges during traditional machining. Electrical discharge machining (EDM) has demonstrated significant potential in improving surface characteristics; however, the integration of powder-suspended EDM (PS-EDM) further enhances machining performance. This study investigates the effects of tungsten carbide (WC) nanoparticle-enriched dielectric fluid on the material removal rate (MRR), microhardness (MH), surface roughness (SR), and microstructural characteristics of Ti-6Al-4V alloy. WC nanoparticles were introduced into the dielectric fluid at varying concentration of 0, 1, 3 and 5 g/L, with continuous mechanical stirring. The controlled EDM parameters included discharge current (I) of 4 A, 6 A, 8 A and pulse on time (T_on) of 30 μs, 50 μs, 70 μs. The results revealed that an optimal WC concentration of 3 g/L, coupled with increasing ‘I’ and ‘T_on’, led to enhanced MRR, MH, while reducing SR. The maximum MRR (0.0223 g/min) and MH (515 HV) were achieved at 3 g/L, 8 A, 70 μs, whereas the lowest SR (2.85 μm) was observed at 3 g/L, 6 A, 50 μs. MH improved by 63.4% compared to the base alloy. Scanning electron microscope (SEM) analysis confirmed a refined surface with minimal defects at 6 A, 50 μs, 3 g/L, whereas deep crater, and nanoparticle agglomeration were evident at 8A, 70 μs, and 5 g/L. This study establishes that WC concentration, ‘I’ and ‘T_on’ significantly influence machining performance and surface integrity during EDM of Ti-6Al-4V alloy. Future research could explore the dispersion of hybrid nanoparticle in bio-based dielectric fluids to optimize machining efficiency and surface characteristics.