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Heinrichs, J., Norgren, S., Jacobson, S., Yvell, K. & Olsson, M. (2019). Influence of cemented carbide binder type on wear initiation in rock drilling – Investigated in sliding wear against magnetite rock. International journal of refractory metals & hard materials, 85, Article ID 105035.
Open this publication in new window or tab >>Influence of cemented carbide binder type on wear initiation in rock drilling – Investigated in sliding wear against magnetite rock
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2019 (English)In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 85, article id 105035Article in journal (Refereed) Published
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-30696 (URN)10.1016/j.ijrmhm.2019.105035 (DOI)000490047100020 ()2-s2.0-85071543465 (Scopus ID)
Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-10-31Bibliographically approved
Engberg, G., Grehk, M. & Yvell, K. (2018). Analysis of the plastic deformation behavior for two austenitic NiCr-steels with different stacking fault energies. Paper presented at International Conference on Computational Materials Science and Thermodynamic Systems. International Journal of Computational Physics Series, 1(1), 137-141
Open this publication in new window or tab >>Analysis of the plastic deformation behavior for two austenitic NiCr-steels with different stacking fault energies
2018 (English)In: International Journal of Computational Physics Series, ISSN 2631-8350, Vol. 1, no 1, p. 137-141Article in journal (Refereed) Published
Abstract [en]

Two austenitic stainless steels, with low and medium stacking fault energies (SFE), 20 mJ/m2 and 30 mJ/m2 respectively, have been studied by conventional tensile tests and in situ tensile tests in a FEG-SEM equipped for EBSD. High angle boundaries (HAB) and low angle boundaries (LAB) with misorientations >= 10o and >= 2o respectively have been determined, and size distributions for the LABs have been derived by linear intercepts. It was found that the size distributions could be described by bimodal lognormal functions. For the steel with highest SFE plastic deformation took place by dislocation slip only while the steel with low SFE deformed by slip and twinning. Using a model for slip based on the evolution of the dislocation density with the generation of dislocations inversely proportional to the mean free distance of slip and recovery of dislocations proportional to the dislocation density the stress strain-curves were analyzed and the results compared with the measured quantities. The mean free distance of slip as evaluated from the stress-strain curve for the steel with the highest SFE correlates very well with the mean size of the LABs intercept. The rate of recovery also gave an expected stress dependence. The stress needed to start deformation twinning was based on the assumption that Shockley partials become completely separated in the slip plane. The thus calculated values for the twinning stress showed an excellent agreement with the observed start of twinning as given by EBSD evaluation of twin boundaries (TB). For the alloy with low SFE both surface grains (in situ test) and bulk grains (from interrupted conventional tests) were studied. The stress needed for slip and twinning of surface grains was, as expected, in the order of 0.5-0.6 times the applied stress.

Place, publisher, year, edition, pages
NSSEL Publishing, 2018
Keywords
Austenitic stainless steels, Electron backscatter diffraction (EBSD), In situ tension test, Grain boundaries, Flow stress model
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-30084 (URN)10.29167/A1I1P137-141 (DOI)
Conference
International Conference on Computational Materials Science and Thermodynamic Systems
Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2019-05-22Bibliographically approved
Surreddi, K. B., Yvell, K., Norgren, S. & Olsson, M. (2018). Characterization of surface degradation and wear damage Of cemented carbide in rock drilling. In: Prof. Staffan Jacobson (Ed.), The 18th Nordic Symposium on Tribology – NORDTRIB 2018: . Paper presented at The 18th Nordic Symposium on Tribology – NORDTRIB 2018, 18-21 June 2018, Uppsala University, Uppsala, Sweden.
Open this publication in new window or tab >>Characterization of surface degradation and wear damage Of cemented carbide in rock drilling
2018 (English)In: The 18th Nordic Symposium on Tribology – NORDTRIB 2018 / [ed] Prof. Staffan Jacobson, 2018Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

In this work, worn top hammer drill bit buttons after underground drifting in Granodiorite are analysed using scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and electron backscatter diffraction (EBSD) to understand the dominant surface failure and wear mechanisms on the flank wear land region, i.e. the outer side of the gauge row cemented carbide buttons. SEM shows that the worn surface of the flank wear land is partly covered with islands of a thin rock material transfer layer and that the exposed cemented carbide show deformed, cracked and fragmented WC grains. AES gives that the transferred rock material is mainly located on the surface but may penetrate into cemented carbide microstructure to a depth of 1-2 WC grain diameters. Finally, EBSD reveals that the deformation of the cemented carbide in the flank wear land region is located to a thin zone, about ~10 μm in depth.

Keywords
Wire drawing; Cemented carbide; Surface degradation; Wear mechanisms
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-28028 (URN)
Conference
The 18th Nordic Symposium on Tribology – NORDTRIB 2018, 18-21 June 2018, Uppsala University, Uppsala, Sweden
Projects
Mikrostrukturell design av hårdmetall för bergborrtillämpningar
Funder
Knowledge Foundation, 20160132
Available from: 2018-06-28 Created: 2018-06-28 Last updated: 2018-06-28Bibliographically approved
Yvell, K. & Engberg, G. (2018). Deformation structures in a duplex stainless steel. Paper presented at THERMEC 2018. Materials Science Forum, 941, 176-181
Open this publication in new window or tab >>Deformation structures in a duplex stainless steel
2018 (English)In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 941, p. 176-181Article in journal (Refereed) Published
Abstract [en]

The evolution of the deformation structure with strain has been studied using electron backscatter diffraction (EBSD). Samples from interrupted uniaxial tensile tests and from a cyclic tension/compression test were investigated. The evolution of low angle boundaries (LABs) was studied using boundary maps and by measuring the LAB density. From calculations of local misorientations, smaller orientation changes in the substructure can be illustrated. The different orientations developed with strain within a grain, due to operation of different slip systems in different parts of the grain, were studied using a misorientation profile showing substantial orientation changes after a true strain of 0.24. The texture evolution with increasing strain was followed by using inverse pole figures (IPFs). The observed substructure development in the ferritic and austenitic phases could be successfully correlated with the stress-strain curve from a tensile test. LABs were first observed in the different phases when the strain hardening rate changed in appearance indicating that cross slip started to operate as a significant dislocation recovery mechanism. The evolution of the deformation structure is concluded to occur in a similar manner in the austenitic and ferritic phases but with different texture evolution for the two phases.

Keywords
Duplex stainless steel, Electron backscatter diffraction (EBSD), Structure-property relationship, Tensile test
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-28343 (URN)10.4028/www.scientific.net/MSF.941.176 (DOI)000468152500030 ()2-s2.0-85064068590 (Scopus ID)
Conference
THERMEC 2018
Available from: 2018-05-09 Created: 2018-08-17 Last updated: 2019-06-10Bibliographically approved
Yvell, K., Grehk, T. M., Hedström, P., Borgenstam, A. & Engberg, G. (2018). EBSD analysis of surface and bulk microstructure evolution during interrupted tensile testing of a Fe-19Cr-12Ni alloy. Materials Characterization, 141, 8-18
Open this publication in new window or tab >>EBSD analysis of surface and bulk microstructure evolution during interrupted tensile testing of a Fe-19Cr-12Ni alloy
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2018 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 141, p. 8-18Article in journal (Refereed) Published
Abstract [en]

Abstract The microstructure evolution in both surface and bulk grains in a pure Fe-19Cr-12Ni alloy has been analyzed using electron backscatter diffraction after tensile testing interrupted at different strains. Surface grains were studied during in situ tensile testing performed in a scanning electron microscope, whereas bulk grains were studied after conventional tensile testing. The evolution of the deformation structure in surface and bulk grains displays a strong resemblance but the strain needed to obtain a similar deformation structure is lower in the case of surface grains. Both slip and twinning are observed to be important deformation mechanisms, whereas deformation-induced martensite formation is of minor importance. Since the stacking fault energy (SFE) is low, 17mJ/m2, dynamic recovery by cross slip of un-dissociated dislocations is unfavorable. This reduces the annihilation of dislocations which in turn leads to a significant increase of low angle boundaries with increasing strain. The low SFE also favors formation of deformation twins which reduces the slip distance, leading to a hardening similar to the Hall-Petch relation. The combination of a low ability for cross-slip and a reduced slip distance caused by twinning is concluded to be the main reason for maintaining a high strain-hardening rate up to strains close to necking.

Keywords
Austenitic stainless steels, Electron backscatter diffraction (EBSD), In situ tension test, Grain boundaries, Grain rotation
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-27537 (URN)10.1016/j.matchar.2018.04.035 (DOI)000435428100002 ()2-s2.0-85046128454 (Scopus ID)
Note

Open Access APC beslut 12/2018

Available from: 2018-04-27 Created: 2018-04-27 Last updated: 2018-08-17Bibliographically approved
Yvell, K. (2018). Experimental Studies of Deformation Structures in Stainless Steels using EBSD. (Doctoral dissertation). KTH Royal Institute of Technology
Open this publication in new window or tab >>Experimental Studies of Deformation Structures in Stainless Steels using EBSD
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis, the focus has been the study of deformation structures in stainless steels by using electron backscatter diffraction (EBSD). Via increased knowledge of the evolution of the substructure during deformation, the design and control of the manufacturing process can be improved.

A relation was found between the active deformation mechanisms, the evolution of low angle boundaries (LABs) and the strain hardening rate. When deformation twinning was an active deformation mechanism in an austenitic stainless steel with lower stacking fault energy (SFE), the strain hardening rate was maintained up to large strains due to formation of LABs. The deformation twin boundaries acted as new obstacles for dislocation slip which in turn increased the formation of LABs even further. During deformation by slip in an austenitic stainless steel with a higher SFE, the strain hardening rate instead decreased when LABs were formed. A high value of SFE promotes dislocation cross slip which in turn increases annihilation of dislocations leading to a minor increase in LAB formation.

Deformation structures formed in surface grains during in situ tensile tests were found to develop at lower strains than in bulk grains obtained from interrupted conventional tensile tests. This behavior is consistent with the fact that dislocations sources and deformation twinning operate at approximately half the stress on a free surface as compared to the bulk.

The deformation structures were quantified by measuring size distributions for entities bounded by LABs and high angle boundaries (HABs). The size distributions were found to be well described by bimodal lognormal distribution functions. The average size for the distribution of small grains and subgrains correlated well with the mean free distance of dislocation slip and to the strain hardening.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2018. p. 63
Keywords
EBSD, Austenitic stainless steels, Duplex stainless steel, In situ tensile test, Grain boundaries, Grain rotation, Grain size distribution, Texture, Strain hardening, Structure-property relationship, High strain rate, Wire rod rolling, Roll forming
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-28340 (URN)978-91-7729-772-7 (ISBN)
Public defence
2018-06-05, B2, Brinellvägen 23, Stockholm, 10:00 (Swedish)
Opponent
Supervisors
Available from: 2018-08-17 Created: 2018-08-17 Last updated: 2018-08-17Bibliographically approved
Yvell, K., Grehk, T. M., Hedström, P., Borgenstam, A. & Engberg, G. (2018). Microstructure development in a high-nickel austenitic stainless steel using EBSD during in situ tensile deformation. Materials Characterization, 135(Supplement C), 228-237
Open this publication in new window or tab >>Microstructure development in a high-nickel austenitic stainless steel using EBSD during in situ tensile deformation
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2018 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 135, no Supplement C, p. 228-237Article in journal (Refereed) Published
Abstract [en]

Plastic deformation of surface grains has been observed by electron backscatter diffraction technique during in situ tensile testing of a high-nickel austenitic stainless steel. The evolution of low- and high-angle boundaries as well as the orientation changes within individual grains has been studied. The number of low-angle boundaries and their respective misorientation increases with increasing strain and some of them also evolve into high-angle boundaries leading to grain fragmentation. The annealing twin boundaries successively lose their integrity with increasing strain. The changes in individual grains are characterized by an increasing spread of orientations and by grains moving towards more stable orientations with 〈111〉 or 〈001〉 parallel to the tensile direction. No deformation twins were observed and deformation was assumed to be caused by dislocation slip only.

Keywords
Austenitic stainless steels, Electron backscatter diffraction (EBSD), In situ tension test, Grain boundaries, grain rotation
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-26645 (URN)10.1016/j.matchar.2017.11.046 (DOI)000423248200027 ()2-s2.0-85035068432 (Scopus ID)
Note

Open Access APC beslut 13/2018

Available from: 2017-11-30 Created: 2017-11-30 Last updated: 2018-08-17
Heinrichs, J., Olsson, M., Yvell, K. & Jacobson, S. (2018). On the deformation mechanisms of cemented carbide in rock drilling: Fundamental studies involving sliding contact against a rock crystal tip. International journal of refractory metals & hard materials, 77, 141-151
Open this publication in new window or tab >>On the deformation mechanisms of cemented carbide in rock drilling: Fundamental studies involving sliding contact against a rock crystal tip
2018 (English)In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 77, p. 141-151Article in journal (Refereed) Published
Abstract [en]

Cemented carbide is a composite material, most commonly consisting of tungsten carbide grains in a metallic matrix of cobalt. The combination of a hard ceramic phase in a ductile metallic matrix combines high hardness and ability to withstand plastic deformation with toughness to avoid cracking and fracturing. Since these properties are very important in rock drilling, cemented carbides are frequently used in such applications. In earlier work, it was found that granite in sliding contact with considerably harder cemented carbides not only results in plastic deformation of the cemented carbide composite, but also in plastic deformation of some of the individual WC grains. The latter observation is remarkable, since even the two hardest granite constituents (quartz and feldspar) are significantly softer than the WC grains. This tendency to plastic deformation of the WC grains was found to increase with increasing WC grain size. The present investigation aims to increase the understanding of plastic deformation of cemented carbides in general, and the individual WC grains in particular, in a situation representative for the rock drilling application. The emphasis is put on explaining the seemingly paradoxical fact that a nominally softer counter material is able to plastically deform a harder constituent in a composite material. The experimental work is based on a scratch test set-up, where a rock crystal tip slides against a fine polished cemented carbide surface under well-controlled contact conditions. The deformation and wear mechanisms of the cemented carbide are evaluated on the sub-micrometer scale; using high resolution FEG-SEM, EDS, EBSD, BIB and FIB cross-sectioning. The size of the Co-pockets, together with the shape and size of WC grains, turned out to be decisive factors in determining the degree of carbide deformation. The results are discussed with respect to their industrial importance, including rock drilling.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Cemented carbides, Deformation, Quartz, Rock drilling, Sliding, Wear
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-28457 (URN)10.1016/j.ijrmhm.2018.04.022 (DOI)000445989200018 ()2-s2.0-85051820047 (Scopus ID)
Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2018-10-19Bibliographically approved
Olsson, M., Yvell, K., Heinrichs, J., Bengtsson, M. & Jacobson, S. (2017). Surface degradation mechanisms of cemented carbide drill buttons in iron ore rock drilling. Wear, 388-389, 81-92
Open this publication in new window or tab >>Surface degradation mechanisms of cemented carbide drill buttons in iron ore rock drilling
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2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, p. 81-92Article in journal (Refereed) Published
Abstract [en]

The wear behavior of cemented carbide rock drill buttons is influenced by many factors, which include the composition and microstructure of the cemented carbide material, the nature of the rock material, and the conditions of the rock drilling operation. Depending on the type of rock and on the drilling procedure used, the cemented carbide is exposed to substantially differing mechanical and thermal conditions. In the present study, the surface degradation and wear mechanisms of cemented carbide drill buttons exposed to iron ore rock drilling have been characterized based on a combination of high resolution scanning electron microscopy (SEM), focused ion beam cross-sectioning (FIB), energy-dispersive X-ray spectroscopy (EDS) and electron back scatter diffraction (EBSD).The results show a significant difference in surface degradation and wear between the front and peripheral buttons of the drill bits. While the front buttons display a relatively smooth worn surface with shallow surface craters the peripheral buttons display a reptile skin pattern, i.e. plateaus, 200-300. μm in diameter, separated by valleys, typically 40-50. μm wide and 15-30. μm deep, The reptile skin pattern is obtained in regions where the peripheral buttons are in sliding contact against the drill hole walls and exposed to high surface temperatures caused by the frictional heating. The results indicate that the reptile skin pattern is related to friction induced thermal stresses rather than mechanical contact stresses, i.e. the reptile skin pattern is formed due to thermal fatigue, rather than mechanical fatigue, caused by the cyclic frictional heating generated at the cemented carbide button/iron ore interface.

Keywords
Cemented carbide, Iron ore, Reptile skin, Rock drilling, Wear mechanisms, Atmospheric temperature, Carbide tools, Carbides, Degradation, Drills, Energy dispersive spectroscopy, Fasteners, Friction, Ion beams, Iron, Iron ores, Ores, Photodegradation, Rock drills, Rocks, Scanning electron microscopy, Stresses, Tribology, Wear of materials, X ray spectroscopy, Cemented carbides, Electron back scatter diffraction, Energy dispersive X ray spectroscopy, High-resolution scanning electron microscopies, Mechanical contact, Surface degradation, Surface temperatures
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-24700 (URN)10.1016/j.wear.2017.03.004 (DOI)2-s2.0-85015717944 (Scopus ID)
Available from: 2017-04-10 Created: 2017-04-10 Last updated: 2018-06-05Bibliographically approved
Yvell, K., Grehk, T. M. & Engberg, G. (2016). Microstructure characterization of 316L deformed at high strain rates using EBSD. Materials Characterization, 122, 14-21
Open this publication in new window or tab >>Microstructure characterization of 316L deformed at high strain rates using EBSD
2016 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 122, p. 14-21Article in journal (Refereed) Published
Abstract [en]

Specimens from split Hopkinson pressure bar experiments, at strain rates between ~ 1000–9000 s− 1 at room temperature and 500 °C, have been studied using electron backscatter diffraction. No significant differences in the microstructures were observed at different strain rates, but were observed for different strains and temperatures. Size distribution for subgrains with boundary misorientations > 2° can be described as a bimodal lognormal area distribution. The distributions were found to change due to deformation. Part of the distribution describing the large subgrains decreased while the distribution for the small subgrains increased. This is in accordance with deformation being heterogeneous and successively spreading into the undeformed part of individual grains. The variation of the average size for the small subgrain distribution varies with strain but not with strain rate in the tested interval. The mean free distance for dislocation slip, interpreted here as the average size of the distribution of small subgrains, displays a variation with plastic strain which is in accordance with the different stages in the stress-strain curves. The rate of deformation hardening in the linear hardening range is accurately calculated using the variation of the small subgrain size with strain.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Austenitic stainless steels, EBSD, High strain rate, Grain size distribution, Strain hardening
National Category
Materials Engineering
Research subject
Steel Forming and Surface Engineering
Identifiers
urn:nbn:se:du-23303 (URN)10.1016/j.matchar.2016.10.017 (DOI)000390728300003 ()
Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2018-08-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4359-4967

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