Exploration and regulation of microstructure of aluminium–vanadium intermediate alloy

In this study, aluminium–vanadium intermediate alloys were prepared via the aluminothermic process, with a specific focus on investigating the microstructure of the AlV85 alloy. The AlV85 alloy is characterized by its hard and brittle nature, and its microstructure is primarily composed of the cubic-structured AlV3 phase, along with aluminium oxide micro-inclusions. Significantly, this microstructure can be regulated by controlling the purity/particle size of raw materials, the unit furnace charge heat, and the material/size of the crucible. Compared with existing research – including studies on AlV55 that did not involve the regulation of the microstructure of high-vanadium alloys, and those focusing on low-vanadium alloys (such as AlV65) that failed to explore the key parameters of high-vanadium alloys – this work innovatively proposes the preparation parameters for high-purity AlV85. These parameters are as follows: vanadium pentoxide with a purity of ≥99.5% and a particle size of ≤5 mm; a unit furnace charge heat of 3200 J·g−1 (this parameter is confirmed for the first time for high-vanadium alloys); and the adoption of a larger-sized magnesia brick crucible. By optimizing based on the aforementioned parameters, the prepared AlV85 alloy has achieved remarkable performance improvements: the oxygen content is <0.05 wt%, and the contents of metallic impurities like Fe and Si are each <0.1 wt%.