The eutectoid compounds are very slow in forming . 共析物的形成是非常缓慢的。
2.
The eutectoid reactions which can occur are extremely sluggish . 可能发生的共折反应是非常缓慢的。
3.
Based on the analysis of eutectoid transformation of sg ( spheroidal graphite ) iron , the numerical model of formation of ferrite and pearlite during the eutectoid transformation was improved 摘要通过对球墨铸铁件共析转变的分析，改进了球铁件中铁素体与珠光体形成的数学模型。
4.
It is indicated that the improved model can calculate the fraction of ferrite and pearlite more accurately , and can specially reflect the effect of both undercooling during the eutectoid transformation and the amount of graphite nodules formed during the process of eutectic reaction on the fraction of pearlite 结果表明，改进的模型可以更准确地预测球铁中铁素体和珠光体的数量，能够准确地体现共析阶段过冷情况和共晶球墨数对珠光体数量的影响。
5.
According to the nb - si phase diagram , the temperature of 1550 ? , which is lower than the eutectoid transformation temperature of nbssi ( 1783 ? ) , is chosen for heat - treatment . according to the present conditions of the furfaces , heat - treatment by stages is first proposed for the nb - si system intermetallic composites to keep the furface in good conditions . the results indicate that the equilibrium nb + nbssia dual - phase microstructure of the nb - si system intermetallics forms gradually via such eutectoid reaction as nbasi ? nb + nbssis with the heat - treatment time 根据nb - si二元相图，选择略低于nb _ 3si共析转变温度t _ f = 1783的1550对铸态nb - si系金属间化合物进行不同时间( 25h - 100h )的热处理，并根据目前国内和我院热处理炉的现状，首次提出采用分段热处理的方法来解决nb - si合金热处理温度高、连续热处理时间过长而影响热处理炉寿命的困难。
