Molten Salt Electrochemical Synthesis, Heat Treatment and Microhardness of Ti–5Ta–2Nb Alloy

Abstract

Alloy of composition Ti5Ta2Nb (numbers in mass%) was synthesised directly from the corresponding mixed metal oxides via the FFC-Cambridge process. Compacted powder discs of TiO 2 Ta 2 O 5 Nb 2 O 5 were cathodically polarised against a graphite anode in a molten CaCl 2 electrolyte, and the effect of various process parameters on the synthesis of the alloy was investigated. The samples retained their disc-type shape throughout the oxide-to-metal conversion under appropriate processing conditions. XRD analysis showed that the electrochemically prepared alloy existed as single-phase ¡-Ti and changed into dual-phase (¡+¢)-Ti upon heat treatment. SEM/EDX analysis revealed a nodular porous microstructure and confirmed the intended chemical composition. Backscattered SEM analysis after heat treatment provided direct evidence of micron-sized ¢-phase precipitates at the boundaries of the ¡-phase particles. Microhardness of the heat-treated alloy compared well with literature data for the same material prepared by conventional metallurgical methods. Overall, the study has demonstrated the feasibility of the single-step electrochemical fabrication of Ti5Ta2Nb alloy bodies directly from oxides for structural application.

Recent Studies on Titanium Refining: 2017–2020

“…Ti5Ta2Nb alloy 25) was synthesized from a TiO 2 Ta 2 O 5 Nb 2 O 5 mixture via the FFC Cambridge process in a molten CaCl 2 electrolyte. It changed into dual-phase (¡ + ¢)Ti by subsequent heat treatment.…”

Study on the Influence of CaO on the Electrochemical Reduction of Fe2O3 in NaCl-CaCl2 Molten Salt

“…In comparison to the MOE method, this process achieves the direct electrolytic production of metals and alloys at lower temperatures ranging from 800 • C to 850 • C [19,20]. The use of solid metal oxides as cathodes in chloride molten salts for a direct electrochemical reduction to produce elemental metals has been applied in the extraction of various metals, including Fe [21,22], Ti [23], Cr [24,25], Al [26], V [27,28], Se [29], titanium-based [30][31][32][33][34], aluminum-based alloys [35,36], high-entropy alloys [37], etc. Research has shown that the addition of a small amount of CaO to CaCl 2 can significantly increase the rate of reduction and deoxidation [38][39][40].…”

Electrochemical Preparation of Ti2CrV Alloy in CaCl2 Melt

“…Numerous titanium-based alloys and intermetallics such as Ti-10 W, Ti-Si, Nb-10Hf-1Ti, Ti-Nb, Ti-5Ta-2Nb, Ti-6Al-4V, Ti-Nb-Sn, Ti-12.5Zr-2.5Nb-2.5Ta, Ti-15Mo, and high entropy alloys, such as TiNbTaZr, TiNbTaZrHf have been synthesized using the FFC Cambridge process. [31][32][33][34][35][36][37][38][39][40] In the case of the Ti-Cr-V family, vanadium-rich V-4Cr-4Ti alloy has been directly prepared electrochemically from the oxides mixture of V 2 O 3 -Cr 2 O 3 -TiO 2 in the molten CaCl 2 -NaCl eutectic at 800 °C. 41 The study reported the influence of cell voltage, sintering temperature, and electrolysis time on the reduction process during the formation of V-4Cr-4Ti alloy.…”