Ni-Fe-Cr: Cr, Fe Grain Boundary Diffusion

The penetration of 51Cr and 59Fe into polycrystalline samples of dual-structure austenitic alloys, at temperatures of between 693 and 1209K, was studied. Serial sectioning was carried out by means of grinding or direct-current glow-discharge sputtering. It was found that the penetration profiles, when plotted as log[concentration] versus the 6/5th-power of the depth, consisted of 2 linear sections. Each of them was attributed to the effect of a particular type of grain boundary. The temperature dependence of the product of the segregation factor, grain boundary width, and grain boundary diffusion coefficient, was of Arrhenius type (tables 118 to 121) for both sections of the profiles. The activation enthalpies for sub-grain boundary diffusion were higher than, or equal to, those for grain boundary diffusion. This was attributed to the existence of a lower degree of structural disorder in the core, and the lattice close to the sub-grain boundary, than in the core and surroundings of grain boundaries.

J.Cermak: Physica Status Solidi A, 1991, 127[1], 53-66

Table 118

Grain Boundary Diffusion of 51Cr in Ni-Fe-Cr Alloys

Fe (wt%)	Cr (wt%)	Temperature (K)	D (m3/s)
0	0	1208	4.46 x 10-21
0	0	1138	1.74 x 10-21
0	0	1068	4.86 x 10-22
0	0	998	1.59 x 10-22
0	0	928	2.74 x 10-23
0	0	858	1.58 x 10-24
20.01	0	1208	3.49 x 10-21
20.01	0	1138	1.03 x 10-21
20.01	0	1068	2.84 x 10-22
20.01	0	998	8.35 x 10-23
20.01	0	928	1.31 x 10-23
41.14	0	1208	1.39 x 10-20
41.14	0	1138	2.13 x 10-21
41.14	0	1068	1.00 x 10-21
62.88	0	1208	1.12 x 10-20
62.88	0	1138	2.61 x 10-21
62.88	0	1068	8.84 x 10-22
9.81	0	1208	7.26 x 10-21
9.81	0	1138	1.08 x 10-21
0	9.81	1068	2.26 x 10-22
0	9.81	998	5.15 x 10-23
0	9.81	858	8.73 x 10-25
9.65	10.17	1208	1.74 x 10-20
9.65	10.17	1138	1.15 x 10-21
9.65	10.17	1068	1.72 x 10-22
9.65	10.17	998	3.90 x 10-23
9.65	10.17	928	3.43 x 10-24
9.65	10.17	858	1.20 x 10-24
28.04	9.36	1208	9.42 x 10-21
28.04	9.36	1138	4.55 x 10-22
28.04	9.36	1068	1.56 x 10-22
28.04	9.36	998	4.75 x 10-23
28.04	9.36	928	1.09 x 10-23
28.04	9.36	858	2.39 x 10-25
63.88	9.64	1208	1.77 x 10-20
63.88	9.64	1138	4.71 x 10-22
63.88	9.64	1068	9.22 x 10-23
63.88	9.64	998	2.77 x 10-23
63.88	9.64	928	1.09 x 10-23
63.88	9.64	858	3.51 x 10-25
0	20.06	1208	2.58 x 10-20
0	20.06	1138	8.07 x 10-21
0	20.06	1068	2.65 x 10-21
0	20.06	998	1.24 x 10-21
0	20.06	928	2.45 x 10-23
0	20.06	858	1.11 x 10-24
10.04	18.98	1208	2.86 x 10-20
10.04	18.98	1138	1.47 x 10-20
10.04	18.98	1068	1.44 x 10-21
10.04	18.98	998	5.00 x 10-22
10.04	18.98	928	2.88 x 10-23
10.04	18.98	858	2.26 x 10-24
37.57	19.99	1208	3.31 x 10-20
37.57	19.99	1138	7.37 x 10-21
37.57	19.99	1068	1.96 x 10-21
37.57	19.99	998	3.25 x 10-22
37.57	19.99	928	5.03 x 10-23
37.57	19.99	858	3.61 x 10-24

Table 119

Grain Boundary Diffusion of 59Fe in Ni-Fe-Cr Alloys

Fe (wt%)	Cr (wt %)	Temperature (K)	D (m3/s)
0	0	1208	1.92 x 10-20
0	0	1138	3.19 x 10-20
0	0	928	2.98 x 10-22
20.01	0	1138	3.48 x 10-20
20.01	0	1068	2.02 x 10-21
20.01	0	998	1.10 x 10-21
20.01	0	928	1.44 x 10-22
20.01	0	858	3.00 x 10-23
41.14	0	1208	4.79 x 10-20
41.14	0	1138	1.60 x 10-20
41.14	0	1068	3.74 x 10-21
41.14	0	998	6.03 x 10-22
41.14	0	928	3.05 x 10-22
41.14	0	858	1.92 x 10-23
62.88	0	1208	3.76 x 10-20
62.88	0	1138	2.13 x 10-20
62.88	0	1068	3.53 x 10-21
62.88	0	998	8.12 x 10-22
62.88	0	928	1.84 x 10-22
62.88	0	858	3.21 x 10-23
0	9.81	1208	1.25 x 10-19
0	9.81	1138	3.45 x 10-20
0	9.81	1068	1.50 x 10-20
0	9.81	998	5.38 x 10-21
0	9.81	928	1.98 x 10-22
0	9.81	958	4.27 x 10-23
9.65	10.17	1208	1.31 x 10-19
9.65	10.17	1138	6.34 x 10-20
9.65	10.17	1068	4.64 x 10-21
9.65	10.17	998	3.27 x 10-21
9.65	10.17	928	8.93 x 10-23
9.65	10.17	858	2.56 x 10-23
28.04	9.36	1208	5.39 x 10-20
28.04	9.36	1138	1.91 x 10-20
28.04	9.36	1068	1.05 x 10-20
28.04	9.36	998	3.90 x 10-21
28.04	9.36	928	8.59 x 10-23
28.04	9.36	858	4.32 x 10-23
63.88	9.64	1208	3.99 x 10-20
63.88	9.64	1138	1.75 x 10-20
63.88	9.64	1068	6.72 x 10-21
63.88	9.64	998	2.65 x 10-21
63.88	9.64	928	1.34 x 10-22
63.88	9.64	858	7.38 x 10-23
0	20.06	1208	4.04 x 10-20
0	20.06	1138	1.43 x 10-20
0	20.06	1068	2.80 x 10-21
0	20.06	998	6.60 x 10-22
0	20.06	928	1.51 x 10-22
0	20.06	858	4.39 x 10-24
10.04	18.98	1208	4.69 x 10-20
10.04	18.98	1138	1.24 x 10-20
10.04	18.98	1068	3.43 x 10-21
10.04	18.98	998	7.89 x 10-22
10.04	18.98	928	6.11 x 10-23
10.04	18.98	858	4.13 x 10-24
37.57	19.99	1208	1.86 x 10-20
37.57	19.99	1138	1.32 x 10-20
37.57	19.99	1068	3.36 x 10-21
37.57	19.99	998	6.13 x 10-22
37.57	19.99	928	3.39 x 10-23
37.57	19.99	858	6.16 x 10-24
0	29.08	1208	2.65 x 10-20
0	29.08	1138	8.33 x 10-21
0	29.08	1068	3.29 x 10-21
0	29.08	998	3.37 x 10-22
0	29.08	928	4.72 x 10-23
0	29.08	858	5.37 x 10-24

Table 120

Sub-Grain Boundary Diffusion of 51Cr in Ni-Fe-Cr Alloys

Fe (wt%)	Cr (wt %)	Temperature (K)	D (m3/s)
41.14	0	1208	1.83 x 10-21
41.14	0	1138	9.46 x 10-22
41.14	0	1068	1.30 x 10-22
41.14	0	998	8.45 x 10-24
41.14	0	928	8.87 x 10-25
41.14	0	858	1.82 x 10-26
62.88	0	1208	2.52 x 10-21
62.88	0	1138	3.50 x 10-22
62.88	0	1068	9.42 x 10-23
62.88	0	998	1.38 x 10-23
62.88	0	928	9.85 x 10-25
62.88	0	858	1.79 x 10-26
0	9.81	1208	2.20 x 10-21
0	9.81	1138	4.72 x 10-23
0	9.81	1068	2.32 x 10-23
0	9.81	998	3.34 x 10-24
0	9.81	928	3.66 x 10-25
0	9.81	858	5.73 x 10-26
9.65	10.17	1208	1.19 x 10-21
9.65	10.17	1138	4.93 x 10-23
9.65	10.17	1068	4.98 x 10-24
9.65	10.17	998	1.52 x 10-24
9.65	10.17	928	5.09 x 10-25
9.65	10.17	858	2.35 x 10-26
28.04	9.36	1208	1.40 x 10-21
28.04	9.36	1138	3.07 x 10-23
28.04	9.36	1068	8.01 x 10-24
28.04	9.36	998	2.76 x 10-24
28.04	9.36	928	2.76 x 10-25
28.04	9.36	858	3.67 x 10-26
63.88	9.64	1208	1.33 x 10-21
63.88	9.64	1138	2.35 x 10-23
63.88	9.64	1068	1.49 x 10-23
63.88	9.64	998	1.47 x 10-24
63.88	9.64	928	1.42 x 10-25
63.88	9.64	858	1 70 x 10-26
0	20.06	1208	3.73 x 10-22
0	20.06	1138	4.74 x 10-23
0	20.06	1068	1.54 x 10-23
0	20.06	998	8.79 x 10-25
0	20.06	928	1.10 x 10-25
0	20.06	858	5.73 x 10-27
10.04	18.98	1208	3.29 x 10-22
10.04	18.98	1138	5.61 x 10-23
10.04	18.98	1068	1.58 x 10-23
10.04	18.98	998	1.16 x 10-24
10.04	18.98	928	1.08 x 10-25
10.04	18.98	858	5.11 x 10-27
37.57	19.99	1208	4.73 x 10-22
37.57	19.99	1138	3.64 x 10-23
37.57	19.99	1068	1.43 x 10-23
37.57	19.99	998	1.05 x 10-24
37.57	19.99	928	1.47 x 10-25
37.57	19.99	858	5.06 x 10-27
0	29.08	1208	2.96 x 10-22
0	29.08	1138	3.32 x 10-23
0	29.08	1068	1.60 x 10-23
0	29.08	998	1.08 x 10-24
0	29.08	928	1.80 x 10-25
0	29.08	858	1.18 x 10-26

Table 121

Sub-Grain Boundary Diffusion of 59Fe in Ni-Fe-Cr Alloys

Fe (wt%)	Cr (wt%)	Temperature (K)	D(m3/s)
0	0	1208	2.43 x 10-21
0	0	1138	2.03 x 10-22
0	0	998	1.02 x 10-23
0	0	928	1.14 x 10-24
0	0	858	1.48 x 10-25
20.01	0	1208	1.81 x 10-21
20.01	0	1138	6.48 x 10-22
20.01	0	1068	1.20 x 10-22
20.01	0	998	1.93 x 10-24
20.01	0	928	1.77 x 10-24
20.01	0	858	2.10 x 10-25
41.14	0	1208	1.58 x 10-21
41.14	0	1138	5.50 x 10-22
41.14	0	1068	1.53 x 10-23
41.14	0	998	2.48 x 10-24
41.14	0	928	5.68 x 10-25
41.14	0	858	7.33 x 10-26
62.88	0	1208	1.64 x 10-21
62.88	0	1138	3.45 x 10-22
62.88	0	1068	1.95 x 10-23
62.88	0	998	1.08 x 10-23
62.88	0	928	4.41 x 10-25
62.88	0	858	7.20 x 10-26
0	9.81	1208	3.75 x 10-22
0	9.81	1138	1.04 x 10-22
0	9.81	1068	1.19 x 10-23
0	9.81	998	4.72 x 10-24
0	9.81	928	3.19 x 10-25
0	9.81	858	1.85 x 10-25
9.65	10.17	1208	7.69 x 10-22
9.65	10.17	1138	3.06 x 10-22
9.65	10.17	1068	1.52 x 10-23
9.65	10.17	998	1.80 x 10-23
9.65	10.17	928	1.56 x 10-24
9.65	10.17	858	3.28 x 10-25
28.04	9.36	1208	4.37 x 10-22
28.04	9.36	1138	9.11 x 10-23
28.04	9.36	1068	1.02 x 10-23
28.04	9.36	998	3.24 x 10-24
28.04	9.36	928	3.31 x 10-25
28.04	9.36	858	1.11 x 10-25
63.88	9.64	1208	2.07 x 10-21
63.88	9.64	1138	4.48 x 10-22
63.89	9.64	1068	3.06 x 10-23
63.88	9.64	928	1.32 x 10-24
63.88	9.64	858	2.25 x 10-25
0	20.06	1208	3.77 x 10-22
0	20.06	1138	6.13 x 10-23
0	20.06	1068	8.65 x 10-24
0	20.06	998	3.11 x 10-24
0	20.06	928	5.76 x 10-25
0	20.06	858	2.97 x 10-26
10.04	18.98	1208	3.05 x 10-22
10.04	18.98	1138	6.39 x 10-23
10.04	18.98	1068	8.53 x 10-24
10.04	18.98	998	6.30 x 10-24
10.04	18.98	928	4.86 x 10-25
10.04	18.98	858	3.23 x 10-26
37.57	19.99	1208	2.62 x 10-22
37.57	19.99	1138	6.96 x 10-23
37.57	19.99	1068	1.65 x 10-23
37.57	19.99	998	4.75 x 10-24
37.57	19.99	928	2.91 x 10-25
37.57	19.99	858	7.07 x 10-26
0	29.08	1208	3.23 x 10-22
0	29.08	1138	3.47 x 10-23
0	29.08	1068	9.66 x 10-24
0	29.08	998	2.55 x 10-24
0	29.08	928	5.76 x 10-25
0	29.08	858	6.90 x 10-26