Zhang Jingyu, Huang Lin, Xiong Ke, Wang Xiaofeng, Wang Zhengyun, Guo Dashan, Li Ziqi, Feng Wei
School of Mechanical Engineering, Chengdu University Chengdu 610106 China
Sichuan Province Engineering Technology Research Center of Powder Metallurgy Chengdu 610106 China.
RSC Adv. 2024 Aug 7;14(34):24741-24748. doi: 10.1039/d4ra03892d. eCollection 2024 Aug 5.
Al CoCrFeNi ( = 0.1, 0.5 and 1) high-entropy alloys (HEAs) were prepared using a spark plasma sintering (SPS) technique combined with aerosol powder. Their microstructure and phase constituents were characterized using an X-ray diffractometer and SEM, and their tensile properties, hardness and compactness were tested. The results show that the crystal structure of the Al CoCrFeNi HEAs changed significantly with the Al content, from the original single face-centered cubic FCC phase (AlCoCrFeNi) to an FCC + BCC structure (AlCoCrFeNi), and then to FCC + BCC + sigma (σ) phase structures (AlCoCrFeNi). Chemical composition analysis showed that the crystal structure transformation was related to the segregation caused by the increased Al content. The hardness of the Al CoCrFeNi HEAs increases with increasing Al content, and the hardness of AlCoCrFeNi reaches a maximum of 507.3 HV. The tensile properties of the alloy show a trend of first increasing and then decreasing with increasing Al content, and the yield strength, ultimate tensile strength and elongation of the AlCoCrFeNi alloy reach maximum values of 527.4 MP, 943.3 MPa and 28.2%, respectively. The fracture mechanism of the AlCoCrFeNi and AlCoCrFeNi alloys is typical ductile fracture, while that of the AlCoCrFeNi alloy is cleavage fracture. The compactness of the alloy increases with the Al content. The samples were also subjected to high-temperature water vapour corrosion, and corrosion products such as AlFeO, CoCrO and NiCrO were found in the Al and Al alloys, whereas no oxide peaks were detected using XRD for the Al alloy. It was also presumed that a very thin alumina film was generated on the surface of the Al alloy, preventing the oxidation of the sample, in combination with the analysis of SEM, EDS and XPS behaviour.
采用火花等离子体烧结（SPS）技术结合气雾化粉末制备了Al含量（= 0.1、0.5和1）的AlCoCrFeNi高熵合金（HEAs）。使用X射线衍射仪和扫描电子显微镜对其微观结构和相组成进行了表征，并测试了它们的拉伸性能、硬度和致密度。结果表明，AlCoCrFeNi高熵合金的晶体结构随Al含量的变化而显著变化，从最初的单一面心立方FCC相（AlCoCrFeNi）转变为FCC + BCC结构（AlCoCrFeNi），然后转变为FCC + BCC + σ相结构（AlCoCrFeNi）。化学成分分析表明，晶体结构转变与Al含量增加导致的偏析有关。AlCoCrFeNi高熵合金的硬度随Al含量的增加而增加，AlCoCrFeNi的硬度最高达到507.3 HV。合金的拉伸性能随Al含量的增加呈现先增加后降低的趋势，AlCoCrFeNi合金的屈服强度、抗拉强度和伸长率分别达到最大值527.4 MPa、943.3 MPa和28.2%。AlCoCrFeNi和AlCoCrFeNi合金的断裂机制为典型的韧性断裂，而AlCoCrFeNi合金的断裂机制为解理断裂。合金的致密度随Al含量的增加而增加。对样品还进行了高温水蒸气腐蚀试验，在Al和Al合金中发现了AlFeO、CoCrO和NiCrO等腐蚀产物，而Al合金经XRD检测未发现氧化物峰。结合扫描电子显微镜、能谱仪和X射线光电子能谱的分析结果，还推测在Al合金表面生成了一层非常薄的氧化铝膜，从而防止了样品的氧化。
