On the microstructure formation in chromium steels rapidly cooled from the semi-solid state

Püttgen, Wolfgang; Hallstedt, Bengt; Bleck, Wolfgang; Uggowitzer, Peter J.

doi:10.1016/j.actamat.2006.09.021

Cited by 75 publications

(53 citation statements)

References 15 publications

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“…Fruitful achievements on the semi-solid deformation and processing behavior of Al alloys [4][5][6][7][8], Mg alloys [9], and steel [10][11][12] show that the alloy in semi-solid state can be processed more easily with the lower deformation resistance and energy cost. Semi-solid forming can improve the formability due to the presence of liquid phase.…”

Section: Introductionmentioning

confidence: 98%

Grain boundary characteristics and tensile properties of Ti14 alloy after semi-solid deformation

Chen

Wei

Zhang

2011

Int J Miner Metall Mater

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The microstructure and room-temperature tensile properties of Ti14, a new α+Ti 2 Cu alloy, were investigated after conventional forging at 950°C and semi-solid forging at 1000 and 1050°C, respectively. Results show that coarse grains and grain boundaries are obtained in the semi-solid alloys. The coarse grain boundaries are attributed to Ti 2 Cu phase precipitations occurred on the grain boundaries during the solidification. It is found that more Ti 2 Cu phase precipitates on the grain boundaries at a higher semi-solid forging temperature, which forms precipitated zones and coarsens the grain boundaries. Tensile tests exhibit high strength and low ductility for the semi-solid forged alloys, especially after forging at 1000°C. Fracture analysis reveals the evidence of ductile failure mechanisms for the conventional forged alloy and cleavage fracture mechanisms for the alloy after semi-solid forging at 1050°C.

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Section: Introductionmentioning

confidence: 98%

Grain boundary characteristics and tensile properties of Ti14 alloy after semi-solid deformation

Chen

Wei

Zhang

2011

Int J Miner Metall Mater

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“…The bearing steel 100Cr6 is also highly suitable. This steel and X210CrW12 have therefore been extensively investigated in terms of the phase formation during processing [30]. Hallstedt et al [31] have also used thermodynamic prediction, suggesting that important criteria are the slope at 50% liquid and the temperature ranges between 40% liquid and 60% for thixocasting and 20% and 40% for thixoforging.…”

Section: Figure 3 Thermodynamic Prediction Of Liquid Fraction Versus mentioning

confidence: 99%

A review of the semi-solid processing of steel

Atkinson

Rassili

2010

Int J Mater Form

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Steel is a particularly challenging material to semi-solid process because of the high temperatures involved and the potential for surface oxidation. Here the experience of semi-solid processing will be reviewed and the current situation in relation to commercial application assessed. The review will include discussion of the range of potential steel materials which are amenable to thixoforming including thermodynamic prediction of suitable alloy compositions.

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“…Another benefit is the possibility to shape high-alloy difficult-to-form materials. Today, thixo-forming of steels focuses predominantly on tool steels of X210Cr12, 100Cr6, HP9/4/30 or M2 types [2][3][4][5][6][7]. The thixo-formed microstructure is typically made up of polyhedral austenite grains embedded in carbide-austenite network.…”

Section: Introductionmentioning

confidence: 99%

Steels with High Temperature Carbides - New Possibilities for Semi-Solid State Processing

Jirková

Rubešová

Pilecek

et al. 2014

SSP

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Abstract. Semi-solid processing of steels is typically studied using high-alloy steels with higher carbon levels, as those offer a long freezing range which is favourable for conducting the process. The drawback to their application is their microstructure which typically consists of austenite grains embedded in ledeburitic network. This type of microstructure typically fails in brittle manner by fracturing along the interface of the hard network and ductile austenite grains. This is why a way was sought to altering or even inverting the configuration of the microstructure. Eventually, suitable steel chemistries were found which allow the inverted microstructure to be obtained. With regard to the high content of alloy additions, these steels have to be made by powder metallurgy methods. Five different steels of this kind were selected for the experimental programme. All contained high amounts of alloying elements and a large fraction of carbides. Their carbon content was taken into account as well, ranging from 0.55 to 3.4 %. Differences between the steels consisted in the levels of major alloying elements, namely chromium, vanadium, molybdenum, tungsten and cobalt. After suitable process parameters were found, semi-solid processing was used to prepare demonstration products. The transition through semi-solid state transformed the ferritic matrix to austeniticmartensitic one, in which the high-stability carbides were retained. The resulting microstructures were of unconventional nature where carbide particles were embedded in tough metal matrix. Their configuration was thus inverted in contrast to the ones typically obtained by semi-solid processing of tool steels. IntroductionKey advantages of processing steels by thixo-forming include simple forming procedures, the capability to make complex-shape products and to use the near net shape forming, as well as higher productivity [1]. Another benefit is the possibility to shape high-alloy difficult-to-form materials. Today, thixo-forming of steels focuses predominantly on tool steels of X210Cr12, 100Cr6, HP9/4/30 or M2 types [2][3][4][5][6][7]. The thixo-formed microstructure is typically made up of polyhedral austenite grains embedded in carbide-austenite network. It was found during mechanical testing that these structures typically fail by brittle fracture propagating along austenite grain boundaries. In response to that, research was undertaken to invert this microstructure configuration into one where the high-stability carbides would be retained and become embedded in austenitic or austeniticmartensitic matrix. One of the available options is to use steels alloyed with suitable carbide formers in order to obtain favourable distributed high-stability carbides [8,9].

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On the microstructure formation in chromium steels rapidly cooled from the semi-solid state

Cited by 75 publications

References 15 publications

Grain boundary characteristics and tensile properties of Ti14 alloy after semi-solid deformation

Grain boundary characteristics and tensile properties of Ti14 alloy after semi-solid deformation

A review of the semi-solid processing of steel

Steels with High Temperature Carbides - New Possibilities for Semi-Solid State Processing

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