付立铭单爱党王巍
金属学报
doi:10.3724/SP.J.1037.2010.00110
通过理论计算并结合实验研究了低碳Nb微合金钢中NbC析出相与Nb固溶原子共同作用对再结晶后奥氏体晶粒长大的影响. 结果表明, Nb的溶质原子拖曳与NbC析出相钉扎共同作用阻碍晶粒长大晶界的迁移, 高温时NbC析出相的钉扎起主要作用, Nb的溶质拖曳效应并不明显, 而相对低温时Nb拖曳对晶粒长大产生明显地抑制作用, 理论计算与实验结果吻合良好; 溶质原子拖曳和析出相的钉扎对抑制晶粒长大的效力可以用p因子来表征, 当p=0时, 以NbC析出的Nb与固溶Nb的量之比达到最优, 抑制晶粒长大效果最好, 当p>0时, 析出相的钉扎能更有效地阻碍晶粒长大, 而p<0时, 溶质原子的拖曳对抑制晶粒的长大更有效; 在常规热轧温度区间或者奥氏体化温度区间内, 只有尺寸不大于10 nm的细小的NbC析出相对再结晶后的晶粒长大才能起到较好抑制作用.
关键词:
晶粒长大
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precipitates pinning
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solute drag
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low carbon Nb-microalloyed steel
YANG Liu Southwestern Jiaotong University
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Chengdu
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ChinaFANG Hongsheng Tsinghua University
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Beijing
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ChinaMENG Zhihe Luoyang Institute of Technology
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China
金属学报(英文版)
A proper addition of Mn to Fe-C alloys could delay the isothermal transformation and change remarkably the TTT-curves to bay-like shape.The concentration of Mn at the α/γ interphase boundary and thir partition between α- and γ- phase were measured by STEM/TEM-EDAX.The results show that the partition of Mn diminishes gradually as the reaction temperature decreases.There exists a certain temperature range with the strong- est Mn concentration spike at the interphase although no Mn partition is found between austenite and ferrite,and this temperature range is correspondent with the bay-temperature on TTT curves of the alloys.It is thus suggests that the change of TTT-curve configuration is due to the partition of alloy elements.The bay-like shape is attributed to the solute drag ef- fect and the solute drag-like effect caused by the enrichment of Mn at the α/γ interphase.
关键词:
TTT curve
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