Martensite Transformation Kinetics in Ultra-fine Grained Medium Mn TRIP Steel
The martensite transformation kinetics in ultra-fine grained transformation-induced plasticity (TRIP) steel was investigated by means of dilatometry.A modified equation based on Koistinen-Marburger’s exponential function was proposed for the martensitic transformation kinetics.The effects of the grain size and the chemical composition of the austenite were considered together with the effect of the undercooling below the Ms temperature in the modified equation.The Ms temperature was lowered and the kinetics of the martensite transformation was retarded with an increasing content of Mn and C in the austenite.The submicron size of retained austenite and the partitioning of Mn and C to austenite during intercritical annealing were two critical factors resulting in an increase of the austenite stability,and the lowering the Ms temperature.However,the ultra-fine grained retained austenite formed in the intercritical annealing had a remarkably accelerated rate of martensite transformation due to the increased number of the nucleation sites per unit volume present in the ultra-fine austenite grains.
martensite transformation kinetics alloy partitioning grain refinement austenite stability ultrafine-grain
LEE Seok-Jae LEE Seawoong DE COOMAN Bruno C
Graduate Institute of Ferrous Technology,Pohang University of Science and Technology,Pohang 790-784,Korea
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-4
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）