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Orowan强化、热错配强化和Hall-Petch强化是纳米颗粒增强镁基复合材料的主要强化机制,纳米颗粒在基体中的分布状态对起主导作用的强化机制具有重要影响。本文中对现有强化机制模型进行了适当修正,以纳米SiC颗粒增强AZ91D复合材料为例,通过理论计算分析了纳米颗粒完全分布于晶内、完全分布于晶界、在晶内晶界上均有分布的三种状态对镁基复合材料屈服强度的影响,并与实验结果进行对比。结果表明:颗粒完全分布于晶内时,增强效果最好,主要增强机制为Orowan强化;颗粒完全分布于晶界上时,增强效果最差,主要增强机制为Hall-Petch强化。颗粒在晶内晶界上均有分布时,多种强化机制共同发挥作用,增强效果随着晶内与晶界上颗粒比例的减小而逐渐减弱。
Orowan strengthening, hot mismatch strengthening and Hall-Petch strengthening are the main strengthening mechanisms of nano-particle reinforced Mg-based composites. The distribution of nano-particles in the matrix has an important influence on the dominant mechanism. In this paper, the existing strengthening mechanism model was properly amended to nano-SiC particles enhanced AZ91D composite material as an example, by theoretical calculations of the nanoparticles are completely distributed in the crystal, completely distributed in the grain boundaries, both in the grain boundaries The distribution of the three states of Mg-based composites yield strength, and compared with the experimental results. The results show that the enhancement effect is best when the particles are completely distributed in the crystal, and the main enhancement mechanism is Orowan strengthening. When the particles are completely distributed on the grain boundaries, the enhancement effect is the worst, and the main enhancement mechanism is Hall-Petch strengthening. When the particles are distributed in the grain boundary, a variety of strengthening mechanisms work together, and the strengthening effect decreases with the decrease of the proportion of particles in the grain boundaries and grain boundaries.