Nanocrystalline Zr3Al made through amorphization by repeated cold rolling and followed by crystallization

Research highlights: → Zr3Al can be made amorphous by repeated cold rolling as concluded from X-ray results. → TEM shows crystalline debris in the as-deformed material. → Heating to 773 K leads to the crystallization of B82 structured nanocrystals (15 nm). → The crystalline debris (of Zr3Al) acts as nuclei for the crystallization of Zr2Al. → When heating to 973 K, the equilibrium L12 phase starts to form. - Abstract: The intermetallic compound Zr3Al is severely deformed by the method of repeated cold rolling. By X-ray diffraction it is shown that this leads to amorphization. TEM investigations reveal that a homogeneously distributed debris of very small nanocrystals is present in the amorphous matrix that is not resolved by X-ray diffraction. After heating to 773 K, the crystallization of the amorphous structure leads to a fully nanocrystalline structure of small grains (10-20 nm in diameter) of the non-equilibrium Zr2Al phase. It is concluded that the debris retained in the amorphous phase acts as nuclei. After heating to 973 K the grains grow to about 100 nm in diameter and the compound Zr3Al starts to form, that is corresponding to the alloy composition.