超细晶粒钢中晶粒尺寸对塑性的影响模型

发布时间：2018-01-26 14:56

本文关键词： 塑性超细晶粒晶粒尺寸位错塞积位错源　出处：《金属学报》2015年07期 　论文类型：期刊论文

【摘要】：以作者前期提出的位错塞积模型为基础,结合断裂强度与晶粒尺寸的关系,建立了晶粒细化导致超细晶粒钢总伸长率降低的临界晶粒尺寸的计算模型.以晶粒尺寸从10 mm减小到0.2 mm为例,计算结果表明,钢的总塑性伸长率随着晶粒尺寸的减小首先呈现增加的趋势,但是当晶粒尺寸减小到大约2.5 mm后,随着晶粒尺寸的减小,钢的总伸长率不仅不再增加,反而出现了显著的降低,这一结果较好地吻合了近期超细晶粒材料研究的实验现象.本工作的研究说明,导致超细晶粒钢伸长率降低的主要机制在于当晶粒细化到一定程度后,晶界对位错源开动的阻力增大,由此导致的可动位错数目显著降低使得应变量显著减少.
[Abstract]:The relationship between fracture strength and grain size is based on the dislocation slug model proposed by the author. The calculation model of critical grain size of ultrafine grain steel resulted from grain refinement is established. The calculation results show that the grain size is reduced from 10 mm to 0.2 mm. The total plastic elongation of steel increases with the decrease of grain size, but when the grain size decreases to about 2.5 mm, with the decrease of grain size, the total elongation of steel does not increase. On the contrary, there is a significant decrease, which is in good agreement with the recent experimental phenomenon of ultrafine grain materials. The main mechanism leading to the decrease of elongation of ultrafine grained steel is that the resistance of grain boundary to the starting of dislocation source increases when the grain grain is refined to a certain extent, and the number of movable dislocations decreases significantly, and the strain variables decrease significantly.
【作者单位】：北京科技大学材料科学与工程学院;安徽工业大学冶金工程学院;
【基金】：国家自然科学基金项目51071026 教育部留学回国人员科研启动基金项目资助~~
【分类号】：TG142.1
【正文快照】： Manuscript received 2014-12-09,in revised form 2015-05-05实现高等级管线钢强韧化的技术关键是利用控轧控冷(thermal mechanical control processing,TMCP)工艺,通过细化晶粒保证管线钢在高强度的水平下得到良好的低温韧性,以满足在北极等高寒地区条件下,管线承受油气输送

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