TY - JOUR
T1 - Studies on primary crystallization of rapidly quenched Al-Ni-Cu-Nd metallic glass by using high resolution transmission electron microscopy
AU - Xiao, Y. D.
AU - Li, W. X.
AU - Jacovkis, D.
AU - Clavaguera, N.
AU - Clavaguera-Mora, M. T.
AU - Rodriguez-Viejo, J.
PY - 2003/10/1
Y1 - 2003/10/1
N2 - 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.
AB - 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.
KW - Al-rich amorphous alloy
KW - Crystallization
KW - Nucleation and growth mechanism
KW - Rapid solidification
M3 - Article
SN - 1006-7191
VL - 16
SP - 407
EP - 415
JO - Acta Metallurgica Sinica (English Letters)
JF - Acta Metallurgica Sinica (English Letters)
IS - 5
ER -