Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

He, S.M.
Van Dijk, N.H.
Schut, H.
Peekstok, E.R.
Van der Zwaag, S.

Applied Sciences

Radiation, Radionuclides and Reactors

2010-03-10

We have investigated the influence of deformation-induced defects on the isothermal precipitation at 550?°C in as-quenched (solute-supersaturated) and annealed (solute-depleted) Fe-Cu and Fe-Cu-B-N alloys by positron annihilation spectroscopy and hardness tests. Using the coincidence Doppler broadening technique, the evolution of local environment at the positron annihilation sites (open-volume defects, Cu precipitates, and matrix) was monitored as a function of the aging time. For all samples, plastic deformation causes a pronounced change in S and W parameters signaling the formation of open-volume defects. For the as-quenched samples, aging results in a sharp decrease in the amount of open-volume defects combined with the rise of a strong copper signature, which can be attributed to preferential copper precipitation at the open-volume defects introduced by plastic deformation. In contrast, the open-volume defects of the annealed samples can only be reduced partially. Both the hardness tests and the positron annihilation spectroscopy indicate that the addition of B and N to the Fe-Cu alloy causes a significant acceleration of the precipitation in the as-quenched alloys.

http://resolver.tudelft.nl/uuid:78bbe9b1-73a8-4776-aa19-f9b3f201fa82

https://doi.org/10.1103/PhysRevB.81.094103

American Physical Society

0163-1829

Physical Review B, 81 (9), 2010

Institutional Repository

journal article

(c) 2010 The Author(s); American Physical Society