ALBERT

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Acta Materialia, Volume 176〈/p〉 〈p〉Author(s): Y. Kobayashi, J. Takahashi, K. Kawakami〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of a pre-deformation with a true strain of 0.5 on the precipitation behavior during isothermal aging at 580 °C in ferritic steel containing 0.03C-0.1Ti-0.20Mn–3Al (mass %) was investigated. Atom probe tomography (APT) analysis revealed that titanium carbide (TiC) precipitates much earlier and more finely in pre-deformed steel than in steel without a pre-deformation. It was found that the precipitation sites of TiC are not only located on the dislocations but are also distributed homogeneously in a matrix in pre-deformed steel. In steel without a pre-deformation, coarse cementite first precipitates during the early stage of aging, and the cementite then dissolves owing to the subsequent precipitation of TiC. Meanwhile, in pre-deformed steel, cementite has difficulty precipitating, and carbon atoms are considered to segregate to high-density dislocations during the early stage of aging prior to the precipitation of TiC. A kinetic model that explains the difference between the precipitation behaviors of steel with and without a pre-deformation is proposed. Moreover, the difference observed between TiC particle strengthening in steel with and without a pre-deformation is discussed.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S135964541930429X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉