【作者】 孙新军； 刘清友； 陈红桔； 董瀚；

【Author】 Sun Xinjun Liu Qingyou Chen Hongju Dong Han Central Iron and Steel Research Institute Beijing 100081

【机构】 钢铁研究总院；

【摘要】 本文利用热模拟单向压缩实验,研究了一种Nb微合金钢变形诱导铁素体相变(DIFT)组织演变的基本特征,并与变形奥氏体连续冷却相变中的组织变化进行了比较。结果表明,变形诱导铁素体相变可分为三个阶段:具有较低形核率的转变初期、具有较高形核率的转变中期以及较低形核率的转变后期。DIFT是一个形核主导的过程,而变形奥氏体的连续冷却相变是一个晶核生长主导的过程。DIFT由于相变伴随形变进行,奥氏体内位错密度可以保持较高水平,从而可以获得较高的形核率;另外晶核的生长和晶粒的长大因变形时间短而受到充分抑制。这是变形诱导铁素体相变能够获得超细晶的重要原因。更多还原

【Abstract】 The microstructure evolution during deformation induced ferrite transformation (DIPT) for a Nb mi croalloyed low carbon steel was investigated by thermal simulating tests, then compared with the microstructure evolution during continuous cooling transformation of work hardening austenite. Results illustrate that DIFT can be divided three stages: the first stage with lower nucleation rate, the second stage with higher nucleation rate and the third stage with lower nucleation rate. DIFT is a nucleation dominant process, i. e. theу→α transformation is mainly accomplished by continuous nucleation, whereas the CCT of deforming austenite is a grain growth dominant process. The nucleation rate of DIFT is relatively high due to the high level of dislocation density within austenite, and the grain growth and coarsening of ferrite are inhibited during DIFT due to the short deformation time, i. e. short transformation time.更多还原