The effect of heat treatment and cold plastic deformation upon diffusion and permeation in Ni-(14 or 20)Cr and Ni-(0 to 25%)Mn was studied by using steady-state flow measurements. At 330 to 470C, the permeation in quenched Ni-Cr was similar to that in pure Ni. It decreased sharply at temperatures of between 470 and 650C (including a change in short-range order). Changes in permeation corresponded to changes in the electrical resistance of the Ni-Cr alloys. At temperatures above 750C, the permeation decreased but the activation energy was unaltered.

V.A.Goltsov, P.V.Geld, V.J.Kosheleva, J.P.Simakov: Uchen. Zap. Permsk. Univ., 1968, 194, 110-6

 

Table 115

Diffusivity of H in IN718

 

Heat Treatment

Do (m2/s)

E (kJ/mol)

cold-rolled 75%

2.82 x 10-7

45.82

980C,2h; a

1.82 x 10-7

45.30

980C,2h; a; 720C,8h; f(50C/h); 620C,8h; a

6.16 x 10-7

51.22

980C,2h; a; 720C,100h; a

8.33 x 10-7

52.05

a: air-cooled, f: furnace-cooled