Akinwekomi Akeem, Akhtar Farid
Division of Materials Science, Luleå University of Technology, 97187 Luleå, Sweden.
Department of Metallurgical and Materials Engineering, Federal University of Technology Akure, Akure 340252, Ondo State, Nigeria.
Materials (Basel). 2023 Jul 28;16(15):5320. doi: 10.3390/ma16155320.
High-entropy alloys (HEA) with superior biocompatibility, high pitting resistance, minimal debris accumulation, and reduced release of metallic ions into surrounding tissues are potential replacements for traditional metallic bio-implants. A novel equiatomic HEA based on biocompatible metals, CrMoNbTiZr, was consolidated by spark plasma sintering (SPS). The relative sintered density of the alloy was about 97% of the theoretical density, indicating the suitability of the SPS technique to produce relatively dense material. The microstructure of the sintered HEA consisted of a BCC matrix and Laves phase, corresponding to the prediction of the thermodynamic CALPHAD simulation. The HEA exhibited a global Vickers microhardness of 531.5 ± 99.7 HV, while the individual BCC and Laves phases had hardness values of 364.6 ± 99.4 and 641.8 ± 63.0 HV, respectively. Its ultimate compressive and compressive yield strengths were 1235.7 ± 42.8 MPa and 1110.8 ± 78.6 MPa, respectively. The elasticity modulus of 34.9 ± 2.9 GPa of the HEA alloy was well within the range of cortical bone and significantly lower than the values reported for commonly used biomaterials made from Ti-based and Cr-Co-based alloys. In addition, the alloy exhibited good resistance to bio-corrosion in PBS and Hanks solutions. The CrMoNbTiZr HEA exhibited an average COF of 0.43 ± 0.06, characterized mainly by abrasive and adhesive wear mechanisms. The CrMoNbTiZr alloy's mechanical, bio-corrosion, and wear resistance properties developed in this study showed a good propensity for application as a biomaterial.
具有卓越生物相容性、高耐点蚀性、最小碎屑堆积以及减少金属离子向周围组织释放的高熵合金（HEA）是传统金属生物植入物的潜在替代品。一种基于生物相容性金属CrMoNbTiZr的新型等原子高熵合金通过放电等离子烧结（SPS）进行固结。该合金的相对烧结密度约为理论密度的97%，表明SPS技术适用于生产相对致密的材料。烧结高熵合金的微观结构由体心立方（BCC）基体和拉夫斯相组成，这与热力学CALPHAD模拟的预测结果相符。该高熵合金的维氏显微硬度整体为531.5±99.7 HV，而单个BCC相和拉夫斯相的硬度值分别为364.6±99.4 HV和641.8±63.0 HV。其极限抗压强度和抗压屈服强度分别为1235.7±42.8 MPa和1110.8±78.6 MPa。该高熵合金的弹性模量为34.9±2.9 GPa，完全在皮质骨的范围内，且显著低于由钛基和铬钴基合金制成的常用生物材料所报道的值。此外，该合金在磷酸盐缓冲盐水（PBS）和汉克斯溶液中表现出良好的抗生物腐蚀性能。CrMoNbTiZr高熵合金的平均摩擦系数为0.43±0.06，主要表现为磨粒磨损和粘着磨损机制。本研究中开发的CrMoNbTiZr合金的机械性能、生物腐蚀性能和耐磨性能显示出作为生物材料应用的良好潜力。
