Multifilamentary Nb/Al-Ge and Nb/Al-Si precursor fabrication using the intermediately rapid heating and quenching technique

A new fabrication method for multifilamentary Nb/Al-Ge and Nb/Al-Si precursors has been developed, where the drawability of those composite wires has been significantly improved by using intermediately a reel-to-reel rapid heating and quenching (RHQ) technique. Unlike the well-known RHQ process for Nb3Al processing, this new RHQ process is specially performed at an early stage of the precursor processing to yield a fine microstructure of the core by solidifying rapidly only the Al alloy core from the molten state, without any reaction with the Nb matrix. Using this technique, not only the workability of the core but also the hardness balance between the matrix and the core can be improved, thereby making the subsequent restack and draw process easier. Based on the optimal process parameters, fabrication of multifilamentary Nb/Al-Ge and Nb/Al-Si precursors with a piece length of 30 m has been achieved as laboratory samples, reducing the matrix ratio.