Microstructures in a carburized steel after isothermal pearlitic treatment  

作　　者：J.Abraham Mathews H.Farahani J.Sietsma R.H.Petrov M.G.Mecozzi M.J.Santofimia 

机构地区：[1]Department of Materials Science and Engineering,Delft University of Technology,Mekelweg 2,2628 CD,Delft,The Netherlands [2]Tata Steel Research&Development,IJmuiden,The Netherlands [3]Department of Electromechanical,Systems and Metal Engineering,Ghent University,Tech Lane Ghent Science park-Campus A Zwijnaarde,Technologiepark 46,Belgium

出　　处：《Journal of Materials Science & Technology》2023年第29期66-75,共10页材料科学技术（英文版）

摘　　要：The influence of carbon concentration variations on pearlite formation(20 h at 600℃)in a case-carburized steel is investigated.The resultant microstructure shows three distinct regions:carburized case,a transition region,and the original core.The microstructural transition from the case to the core regions is observed to be relatively sharp.The investigated region of the carburized case(0.9 wt.%C)con-tains two types of pearlite:ferrite+cementite and ferrite+M_(23)C_(6),where the pearlitic aggregate with M_(23)C_(6)shows faster formation kinetics.The kinetics of pearlite formation in the transition region(0.3 wt.%C)is very slow and is observed with only M_(23)C_(6)carbide.Only around 40%austenite decomposes into pearlite in the transition region,which,in comparison to the carburized case region of 0.9 wt.%C is a fraction that is lower by a factor of two.Pearlite is absent in the investigated core region(0.16 wt.%C).The microstructure in this region is predominantly martensite and pro-eutectoid ferrite,with a fraction of ferrite well below the equilibrium fraction.Ferrite formation in this region is limited by the redistribution of mainly Ni,Mn,and Cr,and their resulting solute drag effect on the austenite/ferrite interface.A ther-modynamic and kinetic argumentation of these observations is provided with the help of thermodynamic data,precipitation simulations,and a general mixed-mode Gibbs energy balance model.

关 键 词：Pearlite formation Carburized steel M 2_(3)C_(6)carbide KINETICS Solute drag 

分 类 号：TG142.1[一般工业技术—材料科学与工程]