High-temperature physical properties and interfacial interactions of B2O3-SiO2-Al2O3-Na2O-based lubricants with Ti-6Al-4V alloy

L Cui and PY Ni and W Lv and Y Li, CERAMICS INTERNATIONAL, 51, 49534-49546 (2025).

DOI: 10.1016/j.ceramint.2025.08.193

Excellent properties of glass lubricants are essential for efficiently manufacturing high-quality titanium alloys through hot extrusion. In this work, B2O3-SiO2-Al2O3-Na2O-based glass was designed and investigated for the Ti-6Al-4V (TC4) alloy extrusion at around 950 degrees C. The melting behavior, wettability and interfacial behavior of the lubricants with TC4 alloy matrix were analyzed from 700 degrees C to 950 degrees C using the sessile drop method. The results showed that the lubricant softening temperature (Ts) ranged from 739.8 degrees C to 782.8 degrees C. Ts value of lubricant was decreased with a decreased TiO2 content and increased B2O3/SiO2 (B/Si) mass ratio and BaO content. The contact angle (B) between the lubricant and the TC4 alloy surface first increased and then decreased when the lubricant was gradually melted from 700 degrees C to 950 degrees C, with B value of lubricant at 950 degrees C below 22.7 degrees. The decrease in B at 950 degrees C with increased content of TiO2 and BaO, and B/Si ratio was partly attributed to the weakening melt network strength induced by these compositional changes. Additionally, micromorphological characterization and molecular dynamics simulations revealed that B2O3 and BaO components in the lubricant primarily reacted with Ti in the metal matrix. This interfacial reaction enhanced the adhesion between the lubricant and the alloy surface, resulting in a reduction of B by up to 4.27 % with prolonged holding time. It indicates that the lubricant can adhere well to the alloy surface and low flow loss, thereby providing effective oxidation protection for the TC4 alloy.

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