Preparation of Homogeneous Nb-Al Intermetallic Compound Sheet by Multi-Layered Rolling and Subsequent Heat Treatment

The intermetallic compound Nb(3)Al is widely investigated because of its high temperature strength, superior superconductivity and relatively small density As Nb(3)Al has an extremely high melting point and lack of deformability, it is impossible to prepare it by using the conventional metallurgy. In this study, a Nb-Al intermetallic compound was prepared by multi-layered roll-bonding of elemental Nb and Al foils The process consisted of the accumulative roll-bonding (ARB) for making a laminated Nb/Al sheet and the subsequent heat treatment promoting a solid-phase reaction in the laminated Nb/Al sheet Accumulated foils were roll-bonded at 573 K The rolling reduction at I pass was similar to 50%, and the final rolling reduction at 4 passes was similar to 94%. A pulsed electric current sintering (PECS) process was used for the subsequent heat treatment The microstructures produced at each processing stage were characterized by X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (S EM) equipped with energy-dispersive X-ray spectroscopy (EDS). A homogeneous intermetallic compound of Nb(3)Al could be obtained after the subsequent heat treatment for 1.8 ks at 873 K and for 0.9 ks at 1673 K