Simultaneous determinations of the interdiffusivity in amorphous samples, and of the self-diffusivity of Ni, permitted the determination of the thermodynamic enhancement factor for interdiffusion. By using thin compositionally graded films which contained an initially thin layer that was enriched in 62Ni. The evolution of the composition profile during annealing was monitored by means of Rutherford back-scattering spectrometry, and that of the 62Ni profile was monitored by means of secondary ion mass spectrometry. The effective thermodynamic factor in the amorphous material at 623K was found to be of the order of 33 during the first hour of annealing of an as-deposited film. It decreased during prolonged annealing. This factor was larger than any previously reported value, and was slightly greater than the value which was expected on the basis of a Darken analysis. N.Karpe, J.P.Krog, J.Bøttiger, N.G.Chechenin, R.E.Somekh, A.L.Greer: Acta Metallurgica et Materialia, 1995, 43[2], 551-8

 

Table 85

Diffusivity of Al in α-Ti Single Crystals

Temperature (K)

D (m2/s)

Orientation

935

2.17 x 10-21

973

1.28 x 10-20

1010

5.92 x 10-20

1036

2.14 x 10-19

||

1036

3.95 x 10-19

1050

2.44 x 10-19

1073

7.67 x 10-19

1073

5.02 x 10-19

||

1093

1.15 x 10-18

1140

5.42 x 10-18

* wrt c-axis