Showing papers by "Miroslav Karlík published in 2002"
TL;DR: In this article, secondary cleavage cracks in the A 508 C1.3 bainitic steel were analyzed using electron backscattering diffraction (EBSD) and scanning electron microscopy (SEM).
79 citations
TL;DR: In this paper, the microstructural characterization and texture evaluation of aluminum sheets produced by both TRC and cold rolling is presented. And the results of the micro-structural analysis of aluminum sheet produced from two different casting procedures are presented.
37 citations
15 Feb 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: The influence of Cr and Ce solutes on the hardness evolution of an Fe 28 at.% Al alloy during isothermal and isochronal annealing in the temperature range 300-1000°C was studied as mentioned in this paper.
Abstract: The influence of Cr and Ce solutes on the hardness evolution of an Fe–28 at.% Al alloy during isothermal and isochronal annealing in the temperature range 300–1000°C was studied. In the Cr-containing alloys, Cr–Fe–(C) precipitates were found after hot working and cooling. These precipitates were dissolved during annealing at 1000°C for 2 h. Subsequent isothermal and isochronal annealing caused their reprecipitation starting above 300°C. Preferentially they nucleate on dislocations, nearest-neighbor antiphase boundaries and subgrain and grain boundaries. It appears that the precipitate formation decreases the hardness of the alloy. The Ce addition and the Ce-containing particles influence neither the formation of Cr–Fe–(C) precipitates nor the evolution of hardness of the alloy.
15 citations
15 Feb 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, annealing experiments were carried out in order to determine the temperature range for the existence of Cr-Fe-C and Ce-containing particles found in the structure of a hot-extruded Fe-28Al-4Cr-0.1Ce (at.%) alloy.
Abstract: Annealing experiments were carried out in order to determine the temperature range for the existence of Cr–Fe–(C) and Ce-containing particles found in the structure of a hot-extruded Fe–28Al–4Cr–0.1Ce (at.%) alloy. The carbon content in the Cr–Fe–C particles ranges from 15 to 30 at.%., the Cr:Fe ratio in the matrix and grain boundary variant of the particles is 7:3, and 6:4, respectively. Cr–Fe particles without carbon were also found. The matrix Cr–Fe–(C) precipitates form as rods or rhomboidal platelets, the grain boundary particles are thin platelets of irregular shape. All Cr–Fe rich particles are completely dissolved after annealing for 2 h at 950°C, and they reappear when the quenched alloy is heated in the temperature range from 300 to 800°C. At 700°C the precipitate is already formed after 5 min of annealing. The Ce-containing particles, mostly 1–10 μm in diameter, present a broad range of compositions. Nevertheless, more than half of the analyzed particles were identified as the Fe 17 Ce 2 compound. The Ce-containing particles do not dissolve even after annealing for 6 h at 1175°C.
8 citations
TL;DR: In this article, a large quantitative fractographic study was carried out on an A508 C1.3 pressure vessel steel in the temperature range corresponding to the ductile-to-brittle transition.
Abstract: A large quantitative fractographic study was carried out onan A508 C1.3 pressure vessel steel in the temperature range corresponding to the ductile-to-brittle transition. Fractographic analyses of fractured Charpy V-notch (CVN) and compact tension (CT) specimens revealed a certain proportion of ductile fracture preceding cleavage, even if the specimens were tested at temperatures below the DBTT. The influence of the ductile tearing on cleavage triggering was studied. In particular, the stress concentrations in CT and/or CVN specimens induced by the presence of an ellipsoidal defect representing the cluster of debonded MnS inclusions were calculated by finite element method and related to the fracture probability given by Beremin model.
4 citations