In the present work, a multi-principle element alloy (MPEA) with the five base elements Al, Cr, Fe, Ni and Ti in equimolar ratio plus additional elements was produced by powder metallurgy (MPEA5). Thereby, the influence of gentle compositional variations on the resulting material properties was investigated. The chosen MPEA compositions are closely related to conventional alloys (for comparison purposes). The goal is to supplement outstanding properties of existing alloys with MPEA-typical properties. For this purpose, the Al, Cr and Ti contents of the produced MPEA were separately reduced to a level as low as 10 mol%. Thereby, the remaining four base elements stay in equimolar proportion to each other. The starting materials were various prealloyed powders and elemental powders. The MPEAs were produced by combining and mechanical alloying of these powders and then were sintered by hot isostatic pressing. From thermodynamic calculation of stable phases it was predicted that the microstructure of MPEA5 consists of BCC- and Heusler-phases. Altering the chemical composition of MPEA5 by lowering the amount of Cr or Ti only resulted in minor changes of distributed phases. Calculation showed the stabilization of the C14_Laves phase (\(\hbox {Fe}_{2}\hbox {Ti}\)) with decreasing amount of Al. Microstructure analysis of the MPEAs via scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction confirmed the predicted phases. Properties analysis of the MPEAs was conducted via measurement of density and hardness tests. MPEA5 showed a measured density of \(6.33 \pm 0.32\) g/cm\(^3\) which coincides well to the predicted density via CALPHAD. MPEA5 reached a remarkable hardness of 839 HV10, which is at least 40% higher than the hardness of the established alloys L718 and W722, even if these were precipitation hardened. The reasons for the high hardness were the observed fine dispersion of the phases and the strong solid solution strengthening in MPEA5 and its modifications. Furthermore, it has been verified that a decrease of the Al amount in MPEA5 led to the formation of the hard C14_Laves-phase and an increase in hardness of the composition up to 912 HV10.

中文翻译：

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粉末冶金生产的AlCrFeNiTi多原理元素合金的表征

在目前的工作中，通过粉末冶金（MPEA5）生产了一种多原理元素合金（MPEA），它具有等摩尔比的五个基本元素Al，Cr，Fe，Ni和Ti加上其他元素。因此，研究了温和的成分变化对所得材料性能的影响。所选的MPEA成分与常规合金密切相关（出于比较目的）。目的是通过MPEA典型特性来补充现有合金的出色特性。为此，将所生产的MPEA的Al，Cr和Ti含量分别降低至低至10mol％的水平。由此，剩余的四个基本元素彼此等摩尔比例保持。起始原料是各种预合金粉末和元素粉末。通过将这些粉末混合并机械合金化来制造MPEA，然后通过热等静压烧结。根据稳定相的热力学计算，可以预测MPEA5的微观结构由BCC和Heusler相组成。通过降低Cr或Ti的量来改变MPEA5的化学组成只会导致分布相的微小变化。计算表明C14_Laves相的稳定性（\（\ hbox {Fe} _ {2} \ hbox {Ti} \）），且Al含量降低。通过扫描电子显微镜，能量色散X射线光谱法和X射线衍射对MPEA的微观结构分析证实了预测的相。通过测量密度和硬度测试进行MPEA的性能分析。MPEA5测得的密度为\（6.33 \ pm 0.32 \）  g / cm \（^ 3 \）与通过CALPHAD预测的密度非常吻合。MPEA5达到了839 HV10的显着硬度，即使经过沉淀硬化，其硬度也比现有合金L718和W722至少高40％。高硬度的原因是观察到的相的精细分散和MPEA5及其变体中的强固溶强化。此外，已经证实，MPEA5中Al量的减少导致硬C14_Laves相的形成，并且直至912HV10，该组合物的硬度增加。