The nucleation and growth of austenite during continuous heating in plain carbon martensite is simulated using classical nucleation and diffusion growth theories assuming that austenite is nucleated on cementite particles at prior austenite grain boundaries and martensite packet, block, and interlath boundaries. A critical nucleus model on the spherical substrate was modified to take into account the influence of the boundary energy on which cementite particles formed. Simulations were carried out using the particle size distribution of cementite measured in an Fe-0.2 mass pct C alloy heated to near eutectoid temperature (Ae₁). Austenite nucleation stopped in a very short time regardless of boundary site or particle size of cementite due to the fast decrease in carbon supersaturation and the depletion of nucleation sites. The fraction of austenite nucleated on cementite at prior austenite boundaries and martensite packet boundaries etc was much greater than that nucleated on cementite at interlath boundaries. While cementite particles dissolved quickly after austenite was nucleated, a large proportion of cementite particles at lath boundaries remained undissolved until they disappeared at 30 °C to 40 °C above Ae₁. The evolution of austenite grain size was also simulated after austenitization was completed, and compared with experiment.

中文翻译：

---

低碳马氏体与多分散渗碳体连续加热时奥氏体形成的模拟

使用经典的成核和扩散生长理论，模拟了在普通碳马氏体中连续加热过程中奥氏体的形核和生长，假设奥氏体在先前奥氏体晶界以及马氏体包，块和层间边界处的渗碳体颗粒上成核。修改了球形基底上的临界核模型，以考虑到边界能对渗碳体颗粒形成的影响。使用在加热到接近共析温度（Ae _1）的Fe-0.2质量pct C合金中测量的渗碳体粒径分布进行模拟）。不论渗碳体的边界位置或粒径如何，奥氏体的成核作用都在很短的时间内停止，这是由于碳过饱和度的快速降低和成核位置的耗尽所致。奥氏体中的原奥氏体边界和马氏体数据包的边界上成核的渗碳体的馏分等为远大于，在条间的边界上成核的渗碳体。奥氏体成核后渗碳体颗粒迅速溶解，但在板条边界的大部分渗碳体颗粒保持不溶，直到它们在高于Ae _1的30°C至40°C时消失。奥氏体化完成后，还模拟了奥氏体晶粒尺寸的变化，并与实验进行了比较。