TY - JOUR
T1 - Diffusion in quasicrystalline Al-Ni-Co and Al-Pd-Mn
AU - Zumkley, Th
AU - Guo, J. Q.
AU - Sai, Ampo
AU - Nakajima, H.
PY - 2000/12/15
Y1 - 2000/12/15
N2 - Diffusion coefficients of 60Co in single decagonal (d-)Al72.2Ni11.8Co16.0 quasicrystals and of 63Ni in single icosahedral (i-)Al70Pd21Mn9 were measured by the radioactive tracer method. The volume diffusion coefficients can be described by an Arrhenius equation. Anisotropic diffusion behaviour was observed in the d-Al-Ni-Co quasicrystals, in which the mobility of Co is slightly faster along the periodic direction. The activation enthalpies for Co diffusion in d-Al-Ni-Co are Q = 277.4 kJ mol-1 (periodic direction), Q = 289.0 kJ mol-1 (aperiodic direction) and for Ni diffusion in i-Al-Pd-Mn Q = 209.0 kJ mol-1. The results are discussed together with data of similar diffusion investigations in icosahedral quasicrystals, and a diffusion mechanism via vacancies is suggested. In addition, we have determined surface self-diffusion coefficients of 60Co in the d-Al-Ni-Co quasicrystalline alloy and have obtained different activation energies of surface diffusion for the periodic (Q = 147 kJ mol-1) and the quasiperiodic direction (Q = 137 kJ mol-1).
AB - Diffusion coefficients of 60Co in single decagonal (d-)Al72.2Ni11.8Co16.0 quasicrystals and of 63Ni in single icosahedral (i-)Al70Pd21Mn9 were measured by the radioactive tracer method. The volume diffusion coefficients can be described by an Arrhenius equation. Anisotropic diffusion behaviour was observed in the d-Al-Ni-Co quasicrystals, in which the mobility of Co is slightly faster along the periodic direction. The activation enthalpies for Co diffusion in d-Al-Ni-Co are Q = 277.4 kJ mol-1 (periodic direction), Q = 289.0 kJ mol-1 (aperiodic direction) and for Ni diffusion in i-Al-Pd-Mn Q = 209.0 kJ mol-1. The results are discussed together with data of similar diffusion investigations in icosahedral quasicrystals, and a diffusion mechanism via vacancies is suggested. In addition, we have determined surface self-diffusion coefficients of 60Co in the d-Al-Ni-Co quasicrystalline alloy and have obtained different activation energies of surface diffusion for the periodic (Q = 147 kJ mol-1) and the quasiperiodic direction (Q = 137 kJ mol-1).
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U2 - 10.1016/S0921-5093(00)01152-7
DO - 10.1016/S0921-5093(00)01152-7
M3 - Article
AN - SCOPUS:0034503855
VL - 294-296
SP - 702
EP - 705
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -