Combustion Microstructures and Frictional Ignition Resistance of Ti-6Al-4V Titanium Alloy

Abstract:

The effects of the contact pressure P_fric and the oxygen concentration c₀ on the ignition resistance of Ti-6Al-4V were studied by friction in oxygen-enriched atmosphere. The relationship of P_fric-c₀ was built to quantitatively describe the ignition resistance, the combustion microstructures were investigated by XRD, SEM and EDS. Further, the principle of improving the ignition resistance was proposed. It indicates that the relationship of P_fric-c₀ obeys parabolic law. The c₀ decreases by 4% when the P_fric increases from 0.1MPa to 0.25MPa, manifesting that the ignition resistance depends on c₀ strongly (or equivalent flow pressure P_eq). The ignition resistance of Ti-6Al-4V is 42.9% of that of TB12. When P_eq varies from 0.1~0.5MPa, the critical ignition temperature Т^* is approximate to 568~461K. Violent sparks form during frictional ignition. The low ignition resistance of Ti-6Al-4V probably results from not only the composite oxides of TiO₂, Al₂O₃ and V₂O₅ generating during ignition which could not prevent the rapid interaction between Ti and O, but also the Al and V elements in the heat-affected zone which could not stop or slow the massive diffusion of O towards the alloy.

• Periodical: Materials Science Forum (Volume 944)
• Pages: 127-134
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.127
• Online since: January 2019
• Authors: Guang Bao Mi*, Xu Huang, Jing Xia Cao, Bao Wang, Chun Xiao Cao
• Keywords: Combustion Microstructures, Ignition Resistance, Mechanism, Titanium Alloy

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