【摘要】：利用Gleeble熱模擬實(shí)驗(yàn)機(jī)、Vickers硬度計(jì)、SEM,HRTEM及DSC研究了淬火態(tài)含Nb和Nb-Mo微合金鋼在升溫過程中碳化物的析出行為.利用經(jīng)典形核長大理論及Avrami方程對(duì)淬火態(tài)鋼中MC型碳化物的析出動(dòng)力學(xué)進(jìn)行了計(jì)算.結(jié)果表明,含Nb和Nb-Mo微合金鋼淬火后以20℃/min的速率加熱至不同溫度水冷,在300和700℃,由于e-碳化物和MC型碳化物析出而出現(xiàn)了硬度峰值.MC型碳化物在650℃左右析出,由于析出強(qiáng)化而硬度上升,與理論計(jì)算得到的MC型碳化物的析出鼻子點(diǎn)溫度約650℃的結(jié)果相一致.Mo進(jìn)入Nb C中降低了Nb C與鐵素體基體的錯(cuò)配度,從而減小了析出相與鐵素體基體間的界面能,使得(Nb,Mo)C析出動(dòng)力學(xué)加快,所以Nb-Mo鋼中析出相粒子分布更為密集,尺寸更為細(xì)小,具有較高的析出強(qiáng)化作用.
[Abstract]:The precipitation behavior of carbides in quenched Nb and Nb-Mo microalloyed steel during heating was studied by using Gleeble thermal simulation machine, Vickers hardness tester, SEM,HRTEM and DSC. The precipitation kinetics of MC carbides in quenched steel was calculated by using classical nucleation growth theory and Avrami equation. The results show that after quenching, the microalloyed steel containing Nb and Nb-Mo is heated to water cooling at different temperatures at the rate of 20 鈩，

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