Silva Tiago, Lopes Augusto
Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
Materials (Basel). 2024 May 15;17(10):2378. doi: 10.3390/ma17102378.
A significant and increasing number of studies have been dedicated to complex concentrated alloys (CCAs) due to the improved properties that these metallic materials can exhibit. However, while most of these studies employ melting techniques, only a few explore powder metallurgy and pressureless sintering as production methods. In this work, a microstructural characterization of AlCrCuFeMnNi CCA samples obtained by powder metallurgy and pressureless sintering using mixtures of powders with different compositions was carried out. One batch of samples (B1) was prepared using commercial powders of Al, Cr, Cu, Fe, Mn, and Ni. Another batch (B2) used mixtures of CrFeMn, AlNi, and Cu powders. A third set of samples (B3) was obtained by adding 1% at. of Mg to the B2 powder. The samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy dispersive spectroscopy, density measurements, and hardness tests. Thermodynamic calculations were also used to complement the microstructural characterization. All the obtained samples exhibited high relative density and hardness values. However, B3 samples showed a higher hardness, attributed to the finer distribution of oxide particles, which was promoted by the presence of Mg during sintering. These last samples presented a hardness/density ratio of 62 HV/(g cm), surpassing that of some martensitic stainless steels and nickel-titanium alloys.
由于这些金属材料能够展现出改进的性能，大量且数量不断增加的研究致力于复杂高熵合金（CCAs）。然而，尽管这些研究大多采用熔炼技术，但只有少数研究探索了粉末冶金和无压烧结作为生产方法。在这项工作中，对通过粉末冶金和无压烧结使用不同成分粉末混合物获得的AlCrCuFeMnNi CCA样品进行了微观结构表征。一批样品（B1）使用Al、Cr、Cu、Fe、Mn和Ni的商业粉末制备。另一批（B2）使用CrFeMn、AlNi和Cu粉末的混合物。第三组样品（B3）通过向B2粉末中添加1%（原子分数）的Mg获得。通过X射线衍射、扫描和透射电子显微镜、能量色散光谱、密度测量和硬度测试对样品进行了表征。还使用热力学计算来补充微观结构表征。所有获得的样品都表现出高相对密度和硬度值。然而，B3样品显示出更高的硬度，这归因于氧化物颗粒更细的分布，这是由烧结过程中Mg的存在促进的。这些最后的样品呈现出62 HV/(g·cm)的硬度/密度比，超过了一些马氏体不锈钢和镍钛合金。
