形变对板条马氏体20CrNi2Mo钢组织演化规律的影响

发布时间：2018-11-14 12:18

【摘要】：在DIL805A/T热模拟试验机上对20CrNi2Mo板条马氏体钢进行了等温单道次轴向热压缩试验,结合光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和显微硬度计,研究了形变量对20CrNi2Mo钢板条马氏体组织演变规律和力学性能的影响。结果表明:20CrNi2Mo钢在压缩变形过程中极易发生动态再结晶,动态再结晶开始的临界应变为0.22。当变形量小于临界应变时,原奥氏体晶粒尺寸变化不大,板条束尺寸增加,板条块宽度减小,小角度晶界所占比例逐渐增大,大角度晶界所占比例逐渐减少;当变形超过临界应变后,随着变形量的增加,原奥氏体晶粒、板条束、板条块逐渐被细化,小角度晶界所占比例先略有减小后逐渐增大。极图分析表明,20CrNi2Mo钢在形变过程中板条块取向逐渐呈现择优分布。
[Abstract]:The isothermal single pass axial compression test of 20CrNi2Mo lath martensite steel was carried out on a DIL805A/T thermal simulator. Combined with optical microscope, (OM), scanning electron microscope, (SEM), electron backscattering diffraction (SEM),) and microhardness tester, the thermal compression test of 20CrNi2Mo lath martensite steel was carried out. The effect of shape variables on the microstructure evolution and mechanical properties of martensite in 20CrNi2Mo steel strip was studied. The results show that dynamic recrystallization is easy to occur in 20CrNi2Mo steel during compression and deformation, and the critical strain at the beginning of dynamic recrystallization is 0.22. When the deformation is less than the critical strain, the grain size of the original austenite changes little, the size of the lath beam increases, the width of the lath decreases, the proportion of the small angle grain boundary increases gradually, and the proportion of the large angle grain boundary decreases gradually. When the deformation exceeds the critical strain, the primary austenitic grain, lath beam and lath are gradually refined with the increase of the deformation amount, and the proportion of small angle grain boundaries decreases slightly and then increases gradually. Pole diagram analysis shows that the plate orientation of 20CrNi2Mo steel gradually exhibits preferential distribution during deformation.
【作者单位】：贵州大学材料与冶金学院;贵州省材料结构与强度重点实验室;高性能金属结构材料与制造技术国家地方联合工程实验室;
【基金】：国家自然科学基金(51461006,51671060)
【分类号】：TG142.1

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