基于过冷奥氏体动态相变的热轧TRIP钢组织控制 Ⅱ.动态相变后冷却速率

来源期刊：金属学报2010年第2期

论文作者：尹云洋 杨王玥 李龙飞 孙祖庆 王西涛

文章页码：161 - 166

关键词：热轧TRIP钢； 过冷奥氏体动态相变(DTUA)； 冷却速率； 显微组织； 力学性能

Key words：hot rolled TRIP steel； dynamic transformation of undercooled austenite(DTUA)； cooling rate； microstructure； mechanical property

摘    要：利用OM,SEM和TEM等研究了动态相变后的冷却速率对基于动态相变的热轧TRIP钢组织控制影响。结果表明,动态相变后的冷却过程中,亚稳的未相变奥氏体会继续以形核为主的方式发生铁素体相变,随着冷却速率的降低,铁素体体积分数增多,铁素体晶粒内的位错回复较为充分,但铁素体晶粒尺寸变化不大,控制一定的冷却速率(30℃/s),可使实验钢组织中铁素体体积分数及位错密度适中,残余奥氏体体积分数较高,具有较好的强度及塑性。

Abstract: TRIP-aided steels are ideal for lightweight automotive applications due to their high strength and ductility.Thermomechanical processing simulations were performed by hot compression on a Gleeble-1500 machine,in order to develop a comprehensive understanding of the effect of cooling rate after dynamic transformation of undercooled austenite (DTUA) on the microstructure evolution and mechanical properties of 0.2C-1.5Mn-0.5Si-1.0Al (mass faction,%) transformation-induced plasticity (TRIP) steel.The results show that the metastable austenite would be transformed to ferrite mainly by means of nucleation during cooling after DTUA.Decreasing the cooling rate after DTUA, the volume fraction of ferrite increase,the static recovery of dislocations in ferrite produced during dynamic transformation could fully take place,thus the density of dislocations in ferrite decreased through by rearranging and merging,but the grain size of ferrite changes little.At the cooling rate of 30℃/s,the investigated steel has a moderate volume fraction of ferrite and dislocation density in ferrite and a higher volume fraction of retained austenite,resulting in the steel having a higher strength and plasticity.