A study was made of the effects of nanoparticles such as Ni3Al on the evolution of vacancy defects, in a face-centered cubic Fe–Ni–Al alloy under electron irradiation, using positron annihilation spectroscopy. It was shown that the nanosized (~4.5nm) intermetallic particles homogeneously distributed in the alloy matrix caused a several-fold decrease in the accumulation of vacancies, as compared to their accumulation in quenched alloy. This effect increased with irradiation temperature. The irradiation-induced growth of intermetallic nanoparticles was also observed in pre-quenched Fe–Ni–Al under irradiation at 573K. Thus, a quantum-dot like positron state in ultra-fine intermetallic particles provided control over the evolution of coherent precipitates, together with vacancy defects, during irradiation and annealing. Possible mechanisms of the absorption of point defects by coherent nanoparticles were considered.

Effects of Intermetallic Nanoparticles on the Evolution of Vacancy Defects in Electron-Irradiated Fe–Ni–Al Material. A.P.Druzhkov, D.A.Perminov, V.L.Arbuzov: Journal of Physics - Condensed Matter, 2006, 18[2], 365-77

 

Table 4

Grain-Boundary Diffusion of 99Mo in Fe76Mo8Cu1B15

Temperature (K)

Condition

D (m3/s)

648

as-quenched

1.64 x 10-26

628

as-quenched

7.38 x 10-27

608

as-quenched

2.03 x 10-27

588

as-quenched

1.40 x 10-27

628

annealed (683K, 1h)

2.08 x 10-26

608

annealed (683K, 1h)

8.37 x 10-27

588

annealed (683K, 1h)

1.71 x 10-27

568

annealed (683K, 1h)

5.37 x 10-28

548

annealed (683K, 1h)

1.83 x 10-28

648

annealed (743K, 1h)

8.74 x 10-26

628

annealed (743K, 1h)

2.29 x 10-26

608

annealed (743K, 1h)

2.56 x 10-26

568

annealed (743K, 1h)

2.77 x 10-27

548

annealed (743K, 1h)

6.95 x 10-28