【摘要】 合金钢变形过程中奥氏体区域内的位错演变行为与析出行为有着密切的关系。为了验证贝氏体细化结构与室温模拟的Fe-40Ni合金纳米级析出相钉扎位错网络结构的关联,本文采用热模拟、金相显微技术和透射电镜(TEM)显微术研究了低碳微合金钢变形后850℃弛豫过程中的析出行为及其对随后冷却过程中形成的贝氏体组织的影响。结果表明,实验用钢的微观组织结构(超细晶贝氏体及马氏体的混合物)在弛豫过程中可以得到有效细化,变形后在850℃弛豫60~200s可以得到最佳的组织细化结果。同时,应变诱导析出的小于10nm的析出相可以有效地钉扎住位错。实验结果与Fe-40Ni合金模拟结果一致。更多还原

【Abstract】 The evolution of dislocations in an austenitic region has a close relationship with the processing of precipitation during the alloy steel deformation.To verify the relevance of the refining structure of bainite and the pining dislocation networks of nano-size precipitation for Fe-40Ni alloy,the thermo-simulation test,metallographic analysis,quantitative measurement and Transmission Electron Microscope(TEM)technique were used to study the precipitation of deformated low carbon microalloyed steel in a relaxation processing at 850℃and its influence on bainite formed during subsequent cooling.The experimental results demonstrate that the microstructures(mixed ultra-fine bainite and martensite)of the tested steel have been refined effectively during relaxation processing and it shows that the optimum refinement can be obtained by 60-200srelaxation after being deformed.Meanwhile,the dislocations can be pinned by the strain-induced precipitation whose sizes are less than 10nm.The experimental results obtained from the tested steel are in a good agreement with that of the Fe-40Ni alloy simulations.更多还原