Effect of Heat Treatment on the Material Property and Cell Viability of Wire Arc Additively Manufactured Ti6Al4 V

Abstract

Wire arc additive manufacturing (WAAM) holds promise for producing medium to large industrial components. Application of WAAM in the manufacturing of biomedical materials has not yet been evaluated. The current study addresses two key research questions: first, the suitability of the WAAMed Ti6Al4V alloy for biomedical applications, and second, the effect of Ti6Al4V’s constituents (α and β phases) on the cell viability. The WAAMed Ti6Al4V alloy was fabricated (as-deposited: AD) using a metal inert gas (MIG)-based wire arc system using an in-house designed shielding chamber filled with argon. Subsequently, samples were subjected to solution treatment (950 °C for 1 h), followed by aging at 480 °C (T1), 530 °C (T2), and 580 °C (T3) for 8 h and subsequent normalization to ambient conditions. Microstructural analysis revealed ∼45.45% of α′-Ti colonies in the as-deposited samples, reducing to 23.26% postaging at 580 °C (T3). The α-lath thickness and interstitial oxygen content in the sample were observed to be proportional to the aging temperature, peaking at 580 °C (T3). Remarkably, during tribocorrosion analysis in simulated body fluid, the 580 °C-aged T3 sample displayed the lowest corrosion rate (7.9 μm/year) and the highest coefficient of friction (CoF) at 0.58, showing the effect of increasing oxygen content in the alloy matrix. Cell studies showed significant growth at 530 and 580 °C by day 7, correlated with higher oxygen content, while other samples had declining cell density. Additionally, optimal metallurgical property ranges were identified to enhance the Ti6Al4V alloy’s biocompatibility, providing crucial insights for biomedical implant development.