Semi-quantitative model of the microstructure development in the high-alloyed iron based alloy during atomization

Materials Research

Peter Grgač¹  Mária Behúlová¹  Roman Moravčík¹  Jana Mesárošová¹ 

[1] ,Slovak University of Technology in Bratislava Faculty of Materials Science and Technology in Trnava Trnava,Slovak Republic

关键词: tool steel of ledeburite type;    gas atomization;    undercooling;    rapid solidification;    recalescence;    dendrite fragmentation;   

DOI  :  10.1590/S1516-14392012005000055

来源: SciELO

【 摘 要 】

The paper deals with the analysis of microstructure formation in the tool steel of ledeburite type Ch12MF4 with the chemical composition of 2.37% C, 12.06% Cr, 1.2% Mo and 4.0 % V [wt. (%)] in the process of nitrogen gas atomization. Three main types of solidification microstructures were observed in rapidly solidified powder particles: dendritic, compound and cellular. Based on the morphological features of microstructures observed in rapidly solidified particles and mathematical modeling of the thermal history of solidifying spherical droplets, the semi-quantitative model of the microstructure development in the Ch12MF4 steel during atomization was suggested. According to this model, it is supposed that the transition from dendritic to partially dendritic (compound) and nondendritic microstructures results from the thermally induced fragmentation of dendrites by the mechanism of their remelting, morphological changes of dendrite fragments and following spheroidization. The intensity of dendrite fragmentation in solidifying particles of different diameters is controlled mainly by the recalescence temperature and duration of quasi-isothermal period of solidification.

【 授权许可】

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