Effect of Boron on Carbide Coarsening at 873 K (600°C) in 9 to 12 pct Chromium Steels
Artikel i vetenskaplig tidskrift, 2012

The addition of small amounts of boron to 9 to 12 pct chromium steels has been found to decrease their creep rate at 823 K to 923 K (550 °C to 650 °C). In this article, the behavior of boron during austenitizing, tempering, and isothermal heat treatment at 873 K (600 °C) is studied using high-resolution microscopy and microanalysis as well as using atomistic modeling. It was found that increasing the boron content from 9 to 40 ppm decreased the coarsening constant of M23C6 by a factor of almost 2. Most of the added boron was incorporated in M23C6. Atomistic modeling showed that boron diffusion in ferrite is dominated by an interstitial mechanism at 873 K (600 °C). However, the generation of vacancies when carbide precipitates dissolve may promote a distribution with substitutional boron atoms. The absence of a fast mechanism for the transition from substitutional to interstitial occupancy will make the slow substitutional boron diffusion in the matrix rate controlling for the coarsening process.

secondary ion mass spectroscopy (SIMS)

energy-filtered transmission electron microscopy (EFTEM)

atom-probe tomography (APT)

density functional theory (DFT)

Författare

Fang Liu

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Chalmers, Teknisk fysik, Materialens mikrostruktur

Dan Fors

Chalmers, Teknisk fysik, Material- och ytteori

Ardeshir Golpayegani

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Chalmers, Teknisk fysik, Materialens mikrostruktur

Hans-Olof Andrén

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Chalmers, Teknisk fysik, Materialens mikrostruktur

Göran Wahnström

Chalmers, Teknisk fysik, Material- och ytteori

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

1073-5623 (ISSN)

Vol. 43 4053-4062

Drivkrafter

Hållbar utveckling

Innovation och entreprenörskap

Styrkeområden

Energi

Materialvetenskap

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

Ämneskategorier

Annan materialteknik

Metallurgi och metalliska material

DOI

10.1007/s11661-012-1205-6