Abstract

In this work, the softening of the hard, NiAl containing, Cr–Fe–Mn–Al–Ni high entropy alloy system by the introduction of Ni₃Al, an intrinsically ductile intermetallic compound, is reported. The alloys were prepared by vacuum arc melting and their phase formation prediction models were verified in terms of the actual presented microstructural features. X-ray analysis revealed the presence of NiAl and Ni₃Al intermetallic compounds in each HEA system group. The microstructure of all six examined alloys in their as-cast condition consisted of two phases (NiAl-rich B2 and FeCr-rich A2) featuring various eutectic morphologies, while spinodal decomposition was evident in every case. The NiAl–Cr pseudo-binary phase diagram was used for the explanation of the solidification sequence in each alloy. In terms of mechanical properties, HRC hardness measurements showed that higher amounts of Ni₃Al can lower the alloys’ hardness up to half its initial value. Finally, dry-sliding wear testing revealed an oxidation-delamination mode of material removal in both HEAs group, while the Ni₃Al containing alloys also exhibited parts of abrasive wear mode.

Graphic Abstract

Hardness vs composition diagram. It can be seen that by adjusting the type and the extent of the intermetallic phase being formed (a—NiAl, b—Ni3Al), the hardness can be controllably modified within a range of 21 to 58 HRC. The related wear rates are also included

中文翻译：

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通过精心控制金属间相的形成来调节（CrFeMn）x（Ni y Al）1-x，（y = 1,3和x = 0.6,0.72,0.80）高熵合金的硬度：组织演变，硬度和干法滑动磨损响应

摘要

在这项工作中，据报道，通过引入本质上易延展的金属间化合物Ni ₃ Al，软化了含有NiAl的Cr-Fe-Mn-Al-Ni高熵合金硬质合金。通过真空电弧熔化制备合金，并根据实际呈现的微观结构特征验证了它们的相形成预测模型。X射线分析表明存在NiAl和Ni ₃每个HEA系统组中的Al金属间化合物。在铸造状态下，所有六种检验合金的微观结构均由具有不同共晶形态的两相组成（富NiAl的B2和富FeCr的A2），而在每种情况下均明显存在旋节线分解。NiAl-Cr伪二元相图用于解释每种合金中的凝固顺序。在机械性能方面，HRC硬度测量表明，较高含量的Ni ₃ Al可使合金的硬度降低至其初始值的一半。最后，干滑动磨损测试显示，在两个HEA组中，材料均以氧化分层的方式去除，而含Ni ₃ Al的合金也表现出部分磨损方式。

图形摘要

硬度与成分图。可以看出，通过调节形成的金属间相（a-NiAl，b-Ni3Al）的类型和程度，可以将硬度控制在21至58HRC的范围内。相关磨损率也包括在内