Preparation Of Nb₃Al Superconductor By Machanical Alloying And Process Optimization

is widely used in high-field magnet, the high phase formation temperature of which is more than 1800℃, and the deviation from right stoichiometry in such a high temperature bring difficulties to the preparation of Nb3Al. In this thesis, low-temperature powder metallurgy is applied to prepare Nb3Al conductor. Because of simple technology and low temperature, the method can greatly reduce the cost of preparation. The impact on the addition of Si is studied further.In this thesis, supersaturated solid solution is formed by mechanical alloying, therefor Nb3Al can be successfully achieved in low temperature. Mechanical alloying was used to synthesize Nb3Al superconductor successfully, and the process was optimization under various preparation conditions.The optimal preparation conditions have been obtained with the milling time of 1 h, the ball to powder ratio of 7:1, the heat treatment temperatures of 900 ℃, the sintered time of 1 h, and a cooling proccess in furnace to room temperature. The highest transition temperature of Nb3Al superconductor prepared by mechanical alloying was 15.50K, which is still below the desired critical temperature of Nb3Al, mostly probably because of the deviation from the stoichiometry.In the study of Si doping, samples doped by Si contained a little amount impurities, and the critical temperature decreased with the increase of the addition mount of Si. The addition of Si failed to improve superconducting properties. The reason why the prepared samples do not possess ideal superconducting properties were analyzed.