Rapidly solidified Al87Ni7Cu3Nd3 metallic glasses, prepared by using melt spinning, were treated under both isothermal and non-isothermal regime. The amorphous ribbon and the annealed samples were examined by means of differential scanning calorimetry, X-ray diffraction and high resolution transmission electron microscopy with selected-area electron diffraction. The results show that, the as-prepared ribbons are fully amorphous and homogeneous in the micron scale, but contain high density of quenched-in clusters or crystallite embryos. Primary crystallization mainly leads to formation of two-phase mixture of α-Al crystal and residual amorphous phase. The annealed ribbons exposed isothermally at 110°C for 5,130 minutes and heated continuously up to less than 310°C at 40°C/min consist of large amount of α-Al fcc crystal nanoparticles dispersed uniformly in an amorphous matrix. A very little amount of finer orthorhombic Al3Ni intermetallics particles exist in the annealed ribbons heated up to 310°C. During primary crystallization, the leading kinetic mechanics to impede the growth of α-Al crystal is soft impingement, instead of geometric impingement.
|Journal||Acta Metallurgica Sinica (English Letters)|
|Publication status||Published - 1 Oct 2003|
- Al-rich amorphous alloy
- Nucleation and growth mechanism
- Rapid solidification