Effect of carbon on copper precipitation in deformed Fe-based alloys studied by positron annihilation spectroscopy

S Zhang,N H Van Dijk,H Schut,E Brück,S Van Der Zwaag

doi:10.1088/1742-6596/443/1/012027

S Zhang, N H Van Dijk + Show 3 more

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https://doi.org/10.1088/1742-6596/443/1/012027

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Abstract

The role of deformation-induced defects and carbon addition on the copper precipitation during aging at 550 °C is investigated in high-purity Fe-Cu-B-N-C alloy samples by Coincidence Doppler Broadening. In samples with 0% and 8% cold pre-strain, the influence of tensile pre-deformation on the precipitation kinetics of copper is studied. The deformation-induced defects are found to enhance the Cu precipitation kinetics. A sharp reduction in open volume defects is accompanied with a strong increase of Cu signature during the initial stage of aging, implying that the open defects (mainly dislocations) act as nucleation sites for Cu precipitates. A comparison of the time evolution of S-W plots between Fe-Cu, Fe-Cu-B-N, and Fe-Cu-B-N-C alloys indicates that the addition of carbon does not alter the Cu precipitation mechanism but decelerates the kinetics.

Highlights

Recently, we studied the copper precipitation behavior in Fe-Cu and Fe-Cu-B-N alloys during aging by positron annihilation spectroscopy and neutron scattering to evaluate the potential contribution of Cu precipitation to self-healing of open volume defects created by prior plastic deformation [1,2]
We investigate the influence of carbon on the copper precipitation during thermal aging in deformed and un-deformed Fe-Cu-B-N-C alloys using positron annihilation spectroscopy
Positron annihilation spectroscopy is a powerful technique to monitor the fine details of the Cu precipitation in a cold rolled Fe-Cu-B-N-C alloy during aging at 550 oC

Summary

Introduction

We studied the copper precipitation behavior in Fe-Cu and Fe-Cu-B-N alloys during aging by positron annihilation spectroscopy and neutron scattering to evaluate the potential contribution of Cu precipitation to self-healing of open volume defects created by prior plastic deformation [1,2]. For copper containing iron-based alloys, it is of importance to clarify the influence of carbon on the Cu precipitation behavior in iron-based alloys. Positron annihilation has successfully been utilized to study the interaction of irradiation-induced vacancies and carbon in the Fe matrix [4,5]. The effect of carbon on the deformation-induced Cu precipitation, has attracted limited attention.

Published under licence by IOP Publishing Ltd

Results and discussion

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Conclusions