Effect of SiC nanoparticle content and milling time on the microstructural characteristics and properties of Mg-SiC nanocomposites synthesized with powder metallurgy incorporating high-energy ball milling
Effect of SiC nanoparticle content and milling time on the microstructural characteristics and properties of Mg-SiC nanocomposites synthesized with powder metallurgy incorporating high-energy ball milling
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DOI：
10.1016/j.ceramint.2020.07.173
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发表时间：
2020-12-01
影响因子：
5.2
通讯作者：
Thornton, Rob
中科院分区：
文献类型：
--
作者：
Ponhan, Kowit;Tassenberg, Karl;Thornton, Rob
制备纳米颗粒均匀分散的镁基纳米复合材料是近年来研究的热点。在目前的研究中，微米级的镁粉末与10，20，和30重量%的SiC纳米颗粒增强合成通过高能球磨使用的研磨时间范围从1到20小时，以克服偏析和团聚的纳米颗粒内的镁基体。然后使用单轴冷压和烧结工艺来固结研磨的纳米复合材料粉末。采用扫描电子显微镜（SEM）、X射线能谱仪（EDS）和X射线衍射仪（XRD）研究了不同球磨时间和SiC纳米颗粒含量对Mg-SiC球磨粉末形貌演变和Mg-SiC烧结样品显微结构特征的影响。此外，一旦固结过程完成，检查Mg-SiC纳米复合材料的相对密度和硬度值。结果表明，随着SiC纳米颗粒含量的增加和球磨时间的延长，Mg粉的平均晶粒尺寸明显减小，得到的纳米复合粉体尺寸更小，且呈等轴状。研磨20 h后，通过EDS生成的元素图谱证实了SiC纳米颗粒在镁基体中的均匀分布，包括高达30%的重量分数。XRD分析表明，随着球磨时间和SiC含量的增加，镁的衍射峰变宽，最大强度降低。在机械合金化过程中，球磨纳米复合粉末中镁和SiC纳米颗粒之间的界面反应没有形成不期望的相。此外，随着研磨时间的增加，Mg-SiC烧结样品的相对密度和硬度值都有所提高。然而，Mg-SiC纳米复合材料的相对密度急剧下降，而硬度显着提高，由于增加的SiC纳米颗粒的含量。
The fabrication of magnesium nanocomposites with a homogeneous dispersion of nanoparticles has recently become an important issue. In the current study, micro-sized magnesium powders reinforced with 10, 20, and 30 wt% SiC nanoparticles were synthesized through high-energy ball milling using milling times ranging from 1 to 20 h to overcome the segregation and agglomeration of nanoparticles within the magnesium matrix. The milled nanocomposite powders were then consolidated using uniaxial cold pressing and sintering processes. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction were employed to investigate the effects of different milling times and contents of SiC nanoparticles on the evolution of the morphology of Mg-SiC milled powders and the microstructural characteristics of Mg-SiC sintered samples. In addition, once the consolidation process was complete, the relative densities and hardness values of the Mg-SiC nanocomposites were examined. The results indicated that as the content of SiC nanoparticles and the milling time increased, finer and equiaxed nanocomposite powders were obtained, and the average crystallite size of the milled magnesium powder significantly decreased. A homogeneous distribution of the SiC nanoparticles, including up to 30% of weight fraction, in the magnesium matrix was confirmed after 20 h of milling by elemental mapping generated by EDS. Additionally, the XRD analysis revealed that the diffraction peaks of the magnesium broadened while their maximum intensities decreased with increasing the milling time and SiC content. No undesirable phases were formed by interfacial reactions between magnesium and SiC nanoparticles in the milled nanocomposite powder during mechanical alloying. Furthermore, the results showed that both the relative density and hardness value of the Mg-SiC sintered sample improved as the milling time increased. However, the relative density of the Mg-SiC nanocomposite drastically decreased while the hardness significantly improved, as a result of increasing the content of SiC nanoparticles.