Analysis of grain boundary effect of bulk polycrystalline materials through nanomechanical characterization
Analysis of grain boundary effect of bulk polycrystalline materials through nanomechanical characterization
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DOI：
10.1088/0022-3727/41/7/074015
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发表时间：
2008-04
期刊：
影响因子：
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通讯作者：
T. Ohmura;K. Tsuzaki
中科院分区：
文献类型：
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作者：
T. Ohmura;K. Tsuzaki
在纳米尺度上对块状多晶材料的压痕变形行为进行了表征，以了解其宏观性能特别是晶界效应的增强因素。与间隙自由钢在单晶界附近和晶内的变形行为相比，在晶界附近较低的外加应力发生塑性起裂，说明晶界是有效的位错源。晶界作为位错运动的屏障，影响了塑性引发后的后续变形。分别对Fe-C回火马氏体的基体强化因子和晶界强化因子进行了评价。晶界的贡献取决于晶界上析出物的形态。结合位错堆积模型和Hall-Petch关系，发现晶界上膜状碳化物的存在对锁紧参数k有显著影响。
Indentation-induced deformation behaviour was characterized in nano-scale for bulk polycrystalline materials to understand strengthening factors of macroscopic properties especially for the grain boundary effect. Compared with deformation behaviour in the vicinity of single grain boundary and grain interior of an interstitial free steel, plasticity initiation occurs at a lower applied stress near the grain boundary, which means the grain boundary is an effective dislocation source. The subsequent deformation after plasticity initiation is affected by the grain boundary as a barrier to dislocation motion. Strengthening factors of matrix and grain boundaries were evaluated separately for the Fe–C tempered martensite. The contribution of grain boundaries depends on the morphology of precipitates on grain boundaries. Combining the dislocation pile-up model and the Hall–Petch relation, the existence of the film-like carbide on the grain boundary remarkably affects the locking parameter k.