主元数对多主元高熵合金组织结构和性能的影响

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The number of the principal elements has significant contributions to the microstructure and performance of the multi-element high-entropy alloys.In order to solve this problem,all alloys were with the equi-atomic ratio,in this paper,four kinds of alloys which separately involved five elements,six elements,seven elements and eight elements were prepared to explore the effect of the number of the principal elements on microstructure and performance.According to the research,these alloys possess simple FCC,BCC or FCC＋BCC structures.With the increasing of the principal elements,the microstructure of the alloys performs the transition trend from dendrite to equiaxed grains.The main reason is that composition under cooling becomes the dominating factor in the solidification of the alloys.There is composition segregation in the alloys.And the hardness also increases when increasing the principle elements.针对多主元高熵合金中主元数对合金组织结构和性能具有显著影响这一问题,在所研究合金均为等摩尔比的条件下,配置五元、六元、七元和八元合金分别为AlFeCuCoCr、AlFeCuNiCrV、Al-FeCuCoNiCrTi及AlFeCuCoNiCrTiV,研究主元数对合金组织结构和性能的影响。研究发现,4种高熵合金均形成了简单的FCC、BCC或FCC＋BCC晶体结构;随着合金主元数目的增加,合金在凝固过程中成分过冷逐渐取代温度过冷占据主导地位,合金组织呈现由树枝状晶向等轴状晶转变的趋势;合金中均存在成分偏析;合金硬度随主元数增加而增加。