Fe-C-Mn-Si低合金钢奥氏体分解的热力学/动力学相关性  

Correlation Between Thermodynamics and Kinetics upon Austenite Decomposition in Fe-C-Mn-Si Low-Alloyed Steel

作　　者：车文侃 宋韶杰[1] 刘峰[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《西安工业大学学报》2017年第4期295-303,共9页Journal of Xi’an Technological University

基　　金：国家自然科学基金项目(51431008);凝固技术国家重点实验室自主研究课题(117-TZ-2015;159-QP-2016)

摘　　要：热力学/动力学相关性是钢铁组织预测和加工工艺确定的必备条件,采用Gleeble热模拟机,研究未变形以及非再结晶区变形20%和40%后Fe-0.2C-1Mn-1Si(质量分数/%)低合金钢奥氏体分解中热力学/动力学相关性规律.结果表明:随冷速增大,奥氏体发生相变的热力学驱动力升高,而相变由动力学能垒较大的扩散型逐渐转变为能垒较小的切变型.非再结晶区变形提高了奥氏体分解的热力学驱动力,同时缺陷的产生降低了扩散型相变的动力学能垒.冷却路径或变形条件的改变通过热力学驱动力和动力学能垒的相关性,导致奥氏体分解中相变组织的不同.The occurring and progressing of phase transformation is reflected in thermodynamics and kinetics, which are not independent of each other. Thermodynamics is closely intertwined with kinetics, and there should be an explicit relationship between thermodynamic driving force and kinetic potential barrier during multi-phase transformation. Through thermo-mechanical simulation and microstruetural analysis,a qualitative investigation about the correlation between thermodynamics and kinetics of phase transformations,involved in the continuous cooling processes of the undeformed and 20% and 40% deformed austenite for Fe-0. 2C-1Mn-ISi （ω/%） low-alloyed steel, has been performed. The results show： As the cooling rate increases, the transformation starting temperature decreases and the transformation products change gradually from diffusive type to displacive type; Deformation of austenite in the non-recrystallization zone not only increases the starting and finishing temperature of ferrite transformation,hut also extendes its cooling rate range; The dislocation stored energy generated in austenite plastic deformation increases the thermodynamic driving force of transformation, and meanwhile the defects provide more nucleation sites and lower the effective activation energy for diffusive growth because of the more diffusion ehannels^Upon the low-temperature phase decomposition of austenite, the thermodynamic driving force and kinetic potential barrier change cooperatively when cooling path or deformation condition varies, ultimately leading to difference of phase transformation products.

关 键 词：低合金钢 奥氏体变形 连续冷却相变 热力学/动力学相关性 

分 类 号：TG142.1[一般工业技术—材料科学与工程]