The diffusion of 54Mn and 59Fe was studied in icosahedral quasi-crystals by using radio-tracer and serial sectioning methods. It was found that the diffusion data (table 29) could be described by Arrhenius expressions of the form:

Mn:    D (m2/s) = 8.91 x 10-4exp[-1.99(eV)/kT]

Fe:     D (m2/s) = 1.63 x 10-2exp[-2.61(eV)/kT]

The results were compared with the limited amount of published data on quasi-crystals, and with data on diffusion in Al and in Fe3Al. The quasi-crystal data were not appreciably different to those for related crystalline materials, where a vacancy-mediated diffusion mechanism was generally thought to operate. No deviations from Arrhenius behavior were detected.

T.Zumkley, H.Mehrer, K.Freitag, M.Wollgarten, N.Tamura, K.Urban: Physical Review B, 1996, 54[10], R6815-8

 

 

 

Table 29

Diffusivity of 54Mn and 59Fe in

Quasicrystalline Al70.4Pd21.2Mn8.4

 

Temperature (K)

Tracer

D (m2/s)

833.4

54Mn

6.92 x 10-16

875.2

54Mn

3.30 x 10-15

930.2

54Mn

1.43 x 10-14

976.2

54Mn

4.81 x 10-14

1071.7

54Mn

3.50 x 10-13

1122.7

54Mn

9.98 x 10-13

833.3

59Fe

2.79 x 10-18

920.2

59Fe

6.65 x 10-17

1023.7

59Fe

2.60 x 10-15

1025.2

59Fe

2.07 x 10-15

1073.2

59Fe

8.95 x 10-15

1074.2

59Fe

1.15 x 10-14

1107.2

59Fe

1.98 x 10-14

1132.2

59Fe

3.64 x 10-14