多主元FeNiMnCr0.75Alx高熵合金微观结构和力学性能的研究

研究了合金中Al含量的增加对铸态FeNiMnCr_0.75Al_x（x=0.25，0.5，0.75，原子分数）高熵合金晶体结构及力学性能的影响。采用X射线衍射仪（XRD）和透射电子显微镜（TEM）对合金的微观结构及形貌进行分析，采用维氏硬度计和MTS万能试验机测试合金的硬度和室温压缩性能。试验结果表明，铸态下，FeNiMnCr_0.75Al_x高熵合金均由bcc和fcc两种晶体结构的相构成。随着Al含量的增加，合金中bcc结构的相的相对含量逐渐增加，导致硬度和压缩屈服强度也随之升高，应变量降低；且Al含量的增加最终也促使合金中无序bcc结构的相逐渐转变为Ni：（Mn+Al）=1：1（原子分数比）型有序bcc结构的相。

Study of Microstructure and Mechanical Properties of FeNiMnCr0.75Alx High-entropy Alloys

In the present work,the effect of the Al content on the microstructure and mechanical properties of FeNiMnCr_0.75Al_x high-entropy alloy have been investigated.The microstructure and morpology were analysed by X-ray diffractometer and Transmission electron microscopy.The hardness and compressive properties were measured by Vickers hardness tester and MTS materials testing machine.From the experimental results,the crystallographic structures of the as-cast alloys consist of the bcc and fcc phases.With the additions of Al content,the relative volume fraction of bcc phase increases,resulting in the increase of the Vickers hardness,yield strength and the decrease of the strain.Morever,the increase of Al content make the bcc phase transform from the disordered phase into the ordered Ni:(Mn+Al)=1:1(atomic fraction ratio) type bcc phase.