Synthesis and machinability assessment of reinforced Ti6Al4V metal matrix composites

Abstract

Titanium metal matrix composites (TiMMCs) offer exceptional specific strength and thermal stability; however, their machinability is severely hindered by abrasive ceramic reinforcements. The aim of this study synthesizes Ti6Al4V-based TiMMCs reinforced with hybrid B4C, ZrO2, SiC, and MoS2 particles via powder metallurgy and optimizes multi-stage machinability through sequential chemical etching, grinding, and polishing, evaluating effects on surface roughness (Ra) and material removal rate (MRR) via Taguchi L9 orthogonal arrays.The result shown as a morphological analysis revealed homogeneous reinforcement distribution, while XRD confirmed in-situ TiC and TiB2 formation via Ti-B4C reactions, enhancing mechanical properties. The optimal B3 composition (7.5 wt.% B4C, 12.5 wt.% ZrO2, 7.5 wt.% SiC, 4 wt.% MoS2, balance Ti6Al4V) achieved 99.11% relative density, 659 HBNmicrohardness compared to base matrix Ti6Al4V 379 HBN microhardness, and 2964 MPa compressive strength compared to base matrix Ti6Al4V 970 MPa comprehensive strength. Taguchi L9 optimization identified A1B2C3D3 for maximum MRR (0.47 gm/min grinding) and A1B1C1D3 for minimum Ra (0.76 µm post-polishing), highlighting efficiency-quality trade-offs, with grinding most effective for stock removal. This study validates a manufacturing protocol that balances superior mechanical properties of hybrid TiMMCs with precise machinability, enabling their use in demanding engineering applications.