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放电等离子烧结快速制备高钪含量铝钪合金

Superfast preparation of Al-Sc alloys with high Sc content by spark plasma sintering

  • 摘要: 采用放电等离子烧结技术制备高钪含量Al-Sc合金, 利用扫描电子显微镜、能谱仪和X射线衍射仪等设备对球磨前后Al-Sc合金粉末的形貌、相组成以及不同温度快速烧结样品的显微组织结构进行观察和分析, 研究烧结温度对Al-Sc合金显微组织的影响。结果表明: 球磨后粉末的形状较规则, 其颗粒尺寸为25~45 μm, 并初步实现了机械合金化, 除Al、Sc相以外, 有少量Al3Sc和AlSc2相生成。放电等离子烧结可实现高钪含量铝钪合金的快速致密化, 成功制备出钪含量30%(质量分数)的铝钪合金, 通过调整烧结工艺参数, 烧结样品的相对密度可达92.19%;当烧结温度高于500℃时, 所得样品致密, 无孔洞, 且无明显晶界; 随着烧结温度的提高, Sc相与第二相融合, 形成Al3Sc、AlSc2等第二相, 存在于合金中, 且Al3Sc相呈现逐渐增强的趋势。

     

    Abstract: Aluminum-scandium alloys with high scandium content by mass were prepared by spark plasma sintering (SPS). The morphology, the phase composition, and the microstructures after sintering at different temperatures of Al-Sc alloy powders were investigated by scanning electron microscope (SEM), energy dispersive spectrometry (EDS), and X-ray diffractometry (XRD). The effect of sintering temperature on the microstructure of Al-Sc alloys was studied in the paper. The results show that, the Al-Sc alloy powders after ball milling are regular with the particle size of 25~45 μm, and the mechanical alloying of Al-Sc alloy powders is realized initially. In addition to the Al and Sc phases, a small amount of Al3Sc and AlSc2 are generated. The spark plasma sintering can realize the rapid densification of Al-Sc alloy with high scandium content, the Al-Sc alloy with 30% Sc by mass is successfully produced by SPS method. By adjusting the SPS process parameters, the relative density of sintered sample can be improved to 92.19%. The samples with the higher density and non-obvious grain boundary are achieved at the sintered temperature above 500℃. The second phases of Al3Sc and AlSc2 are formed by the combination of Sc with the increase of sintering temperature, and the peak intensity of Al3Sc increases gradually.

     

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