Fracture Micro Mechanism of Cryogenically Treated Ledeburitic Tool Steel

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F22%3A00560104" target="_blank" >RIV/68081723:_____/22:00560104 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1007/978-981-16-8810-2_6" target="_blank" >http://dx.doi.org/10.1007/978-981-16-8810-2_6</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/978-981-16-8810-2_6" target="_blank" >10.1007/978-981-16-8810-2_6</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Fracture Micro Mechanism of Cryogenically Treated Ledeburitic Tool Steel

Popis výsledku v původním jazyce

Fracture micro mechanism of cryogenically treated Cr-V ledeburitic tool steel was studied on fracture toughness testing specimens, by using the scanning electron microscopy and microanalysis. Experimental steel has been processed at different combinations of cryogenic temperatures (from the range75 to269 degrees C) and tempering regimes, producing different microstructures (martensite, retained austenite, carbides), hardness- and fracture toughness values (from the ranges 700-1000 HV and 13-20 MPa x m(1/2), respectively). Conventionally quenched the same steel was considered as a reference. Generally, the obtained fracture surfaces manifest combined low-energetic ductile/cleavage crack propagation mode. The low-energetic ductile mode is associated with the presence of small globular carbides (size < 0.3 mu m) that are produced by cryogenic treatments. On the other hand, cleavage mode is more pronounced with increased matrix stiffness, which is caused by the precipitation of nano-scaled transient carbides within the martensite. Also, differences in role of crack propagation between various carbides were determined. These differences are caused by crystallography of these phases as well as by their size. While small globular carbides (cementite) and dominant amount of the eutectic carbides (cubic MC-phase) assist more probably (by 50-60%) in ductile micro mechanism the coarser secondary particles (hexagonal M7C3-phase) are much more prone to cleavage cracking. This tendency increases with decreasing steel hardness since the matrix becomes more plastic, and the carbides cannot deform together with the matrix as they are much more brittle.

Název v anglickém jazyce

Fracture Micro Mechanism of Cryogenically Treated Ledeburitic Tool Steel

Popis výsledku anglicky

Fracture micro mechanism of cryogenically treated Cr-V ledeburitic tool steel was studied on fracture toughness testing specimens, by using the scanning electron microscopy and microanalysis. Experimental steel has been processed at different combinations of cryogenic temperatures (from the range75 to269 degrees C) and tempering regimes, producing different microstructures (martensite, retained austenite, carbides), hardness- and fracture toughness values (from the ranges 700-1000 HV and 13-20 MPa x m(1/2), respectively). Conventionally quenched the same steel was considered as a reference. Generally, the obtained fracture surfaces manifest combined low-energetic ductile/cleavage crack propagation mode. The low-energetic ductile mode is associated with the presence of small globular carbides (size < 0.3 mu m) that are produced by cryogenic treatments. On the other hand, cleavage mode is more pronounced with increased matrix stiffness, which is caused by the precipitation of nano-scaled transient carbides within the martensite. Also, differences in role of crack propagation between various carbides were determined. These differences are caused by crystallography of these phases as well as by their size. While small globular carbides (cementite) and dominant amount of the eutectic carbides (cubic MC-phase) assist more probably (by 50-60%) in ductile micro mechanism the coarser secondary particles (hexagonal M7C3-phase) are much more prone to cleavage cracking. This tendency increases with decreasing steel hardness since the matrix becomes more plastic, and the carbides cannot deform together with the matrix as they are much more brittle.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20501 - Materials engineering

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON FRACTURE, FATIGUE AND WEAR, FFW 2021

ISBN

978-981-16-8809-6

ISSN

2195-4356

e-ISSN

2195-4364

Počet stran výsledku

14

Strana od-do

67-84

Název nakladatele

Springer

Místo vydání

Singapore

Místo konání akce

Ghent

Datum konání akce

2. 8. 2021

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000833449600006