| 1. |
- Domeij, Björn, 1988-, et al.
(författare)
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Quantification of dendritic austenite after interrupted solidification in a hypoeutectic lamellar graphite iron
- 2016
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Ingår i: Metallography, Microstructure, and Analysis. - New York : Springer. - 2192-9270 .- 2192-9262. ; 5:1, s. 28-42
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an unconventional etching technique to reveal the microstructure in a hypoeutectic lamellar graphite iron that has been quenched after isothermal heat treatment in the proeutectic semi-solid temperature region. A technique for quantifying the dendrite microstructure using the aforementioned etching technique involving a combination of a raster graphics editor and an image analysis software is outlined. The agreement between this quantification technique with regard to volume fraction and surface area per unit volume of the dendritic austenite and corresponding point counting and line intercept techniques is analyzed. The etching technique was found useful but sporadic tinting of martensite was problematic. Some measurements showed significant systematic disagreement which correlated with the coarseness of the measured dendrites. Most systematic disagreement is attributed to difficulties in defining the dendrite boundary in the analogues and much of the random disagreement to easily identified discrepancies between the analogue and the micrograph.
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| 2. |
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| 3. |
- Hernando, Juan Carlos
(författare)
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Can you identify the microstructure?
- 2017
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Ingår i: Metallography, Microstructure, and Analysis. - : Springer. - 2192-9262 .- 2192-9270. ; 6:4, s. 362-363
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Lyu, Yezhe, 1987-
(författare)
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Abrasive Wear of Compacted Graphite Cast Iron with Added Tin
- 2019
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Ingår i: Metallography, Microstructure, and Analysis. - : Springer. - 2192-9262 .- 2192-9270. ; 8:1, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- The abrasive wear behavior of traditional compacted graphite cast iron (CGI) and compacted graphite cast iron with 0.1% tin addition (CGI-Sn) is studied using a pin-on-disk tribometer. The microstructures of these two CGIs were observed by optical microscopy and scanning electron microscopy. The results show that Sn reduces the average size of vermicular graphite and promotes the generation of pearlite. Sn narrows the average lamellar spacing of pearlite. In the wear tests, CGI-Sn yields a decreased wear loss by 16.5% compared with CGI. Both CGI and CGI-Sn show typical abrasive worn morphology, while CGI presents a more severe wear condition in which large fragmentations can be seen. Under the current test condition, Sn is likely to improve the abrasive wear resistance of compacted graphite iron. Further studies of the specific working conditions are needed, such as testing against frictional material in braking systems, to check the validity of the findings.
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| 5. |
- Rehan, M. Arbab, et al.
(författare)
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EBSD Analysis of Blocky Structures in Hardened and Tempered Microstructures of a 5 wt.% Cr Cold Work Tool Steel
- 2021
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Ingår i: Metallography, Microstructure, and Analysis. - : Springer Science and Business Media LLC. - 2192-9270 .- 2192-9262. ; 10:6, s. 862-875
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Tidskriftsartikel (refereegranskat)abstract
- The hardened microstructure of 5 wt.% Cr cold work tool steels is mainly martensitic with significant amount of retained austenite and some undissolved carbides. Whereas the microstructure after tempering shows significant amounts of angular shaped blocky regions, which are interpretated as retained austenite or fresh martensite. The distinction between the phases is difficult due to the morphological similarities. Therefore, the blocky regions are characterized by electron backscatter diffraction to better understand the microstructures. The results showed that the characterisation of blocky structures in the microstructure of a 5 wt.% Cr cold work tool steels varied according to the austenitisation and tempering temperatures as well as the holding time at the tempering temperature. Electron backscatter diffraction of as-quenched microstructures revealed that the blocky structures were either retained austenite, fresh martensite or a combination of large part of fresh martensite with minute amounts of retained austenite. The blocky structures were entirely retained austenite after tempering at 200 °C. Tempering at 525 °C, for holding times of 0.1 or 0.5 h, more blocky regions were retained austenite contrasting to the blocky regions for holding times of 1 or 2 h, which were largely fresh martensite. It was further concluded that electron backscatter diffraction is a suitable technique for characterisation of blocky structures provided that the specimens are prepared by electro-polishing while X-ray diffraction is best suited for a bulk measurement of retained austenite.
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| 6. |
- Rubin, Per, et al.
(författare)
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Graphite Formation and Dissolution in Ductile Irons and Steels Having High Silicon Contents: Solid-State Transformations
- 2018
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Ingår i: Metallography, Microstructure, and Analysis. - New York : Springer. - 2192-9262 .- 2192-9270. ; 7:5, s. 587-595
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Tidskriftsartikel (refereegranskat)abstract
- Graphite formation in the solid state is both in ductile cast irons and in steels strongly promoted by high silicon contents above 3 wt.% Si. The matrix microstructure in austempered ductile iron can be further refined by secondary graphite if the austenitization, quench, and isothermal transformation into ausferrite are preceded by an austenitization at a slightly higher temperature followed by quench to martensite, resulting in higher carbon content than being soluble at the second austenitization temperature. Hypoeutectoid steels with high silicon contents can be rapidly graphitized, causing recrystallization of surrounding ferrite due to plastic deformation making room for less dense graphite. In rolled steels, the interface between manganese sulfide and steel matrix is the most common nucleation site. Voids are formed when graphite is partly or completely dissolved during austenitization in succeeding hardening heat treatments, but the mechanical properties can still be good if the graphite particles dissolved into voids are below 20 µm. Graphitized Si-solution strengthened ferritic steels may perform similar to free-cutting steels but with improved mechanical properties.
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| 7. |
- Suo, Jiao, et al.
(författare)
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Formation of Laves Phase in Sanicro 25 Austenitic Steel During Creep-Rupture Test at 700 degrees C
- 2019
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Ingår i: METALLOGRAPHY MICROSTRUCTURE AND ANALYSIS. - : SPRINGER. - 2192-9262 .- 2192-9270. ; 8:2, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms for the formation of Laves phase located at grain boundaries and in grain interiors in Sanicro 25 steel after creep-rupture test at 700 degrees C and 150/180MPa for 9862/5665h were studied, respectively. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometer, and multi-phase separation technology analysis reveals that Laves phase particles nucleated adjacently either to Si-enriched spots present in the bulky M23C6 carbides or to the grain boundary areas rich in Si, which made the bulky M23C6 carbides gradually divide into small pieces and eventually resulted in the formation of a refined mixture of M23C6 and Laves phase at grain boundaries. Laves phase particles formed independently in austenitic matrix and also dependently at interfaces between austenitic matrix and Z phase in grain interiors. The size and morphology of Laves phase formed at grain boundaries (in M23C6 carbides) and in grain interiors (austenitic matrix) are different. It is hoped that the presented findings will be helpful to understand the Laves phase formation and the grain boundary precipitate refinement correlated with good mechanical properties of this class of austenitic steels/alloys.
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