包晶合金定向凝固中的共生生长

对包晶合金定向生长特性进行分析，并与共晶系经典共生生长模型（Jackson-Hunt模型）所描述的共生生长特性进行对比，提出包晶稳态过热共生生长模型，同时以Fe-Ni合金系为对象，对其亚包晶和过包晶成分在不同温度梯度G和生长速度1，下进行定向凝固实验及组织分析。研究结果表明：在定向凝固条件下，包晶系两相严格的共生生长只有在进入稳态且温度高于包晶相变温度时才可能进行；包晶合金两相的共生生长尤其在G／v值高的平／胞界面形态，确实发生在Tp温度以上，与提出的模型所预测的一致。

Coupled growth in directional solidification of peritectic alloys

The growth characteristic of peritectic alloy during directional solidification was analyzed theoretically and compared with the growth characteristic described in the classical eutectic coupled growth model(Jackson-Hunt model),and a superheating steady state coupled growth model for peritectic alloy was presented.The microstructures of Fe-Ni peritectic system with hypo-and hyper-composition directionally solidified were investigated at different temperature gradients and growth velocities.The results show that the strict coupled growth between primary and peritectic phases only takes place at the temperature higher than peritectic phase transformation temperature in steady state.The temperature of coupled growth of the two solid phases is really above the peritectic reaction temperature.The theoretical and experimental results are confirmed each other.