scholarly journals Influence of Molybdenum on the Microstructure, Mechanical Properties and Corrosion Resistance of Ti20Ta20Nb20(ZrHf)20−xMox (Where: x = 0, 5, 10, 15, 20) High Entropy Alloys

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 393
Author(s):  
Karsten Glowka ◽  
Maciej Zubko ◽  
Paweł Świec ◽  
Krystian Prusik ◽  
Magdalena Szklarska ◽  
...  

The presented work was focused on investigating the influence of the (hafnium and zirconium)/molybdenum ratio on the microstructure and properties of Ti20Ta20Nb20(ZrHf)20−xMox (where: x = 0, 5, 10, 15, 20 at.%) high entropy alloys in an as-cast state. The designed chemical composition was chosen due to possible future biomedical applications. Materials were obtained from elemental powders by vacuum arc melting technique. Phase analysis revealed the presence of dual body-centered cubic phases. X-ray diffraction showed the decrease of lattice parameters of both phases with increasing molybdenum concentration up to 10% of molybdenum and further increase of lattice parameters. The presence of two-phase matrix microstructure and hafnium and zirconium precipitates was proved by scanning and transmission electron microscopy observation. Mechanical property measurements revealed decreased micro- and nanohardness and reduced Young’s modulus up to 10% of Mo content, and further increased up to 20% of molybdenum addition. Additionally, corrosion resistance measurements in Ringers’ solution confirmed the high biomedical ability of studied alloys due to the presence of stable oxide layers.

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1017
Author(s):  
Yang Shao ◽  
Huan Ma ◽  
Yibing Wang

In order to reveal the effect of Mo addition on the microstructure and mechanical properties, (CoCuFeNi)100-xMox (x = 0, 10, 15, 19, and 25, x values in atomic ratio) high entropy alloys were prepared by vacuum arc-melting. The results showed that with Mo addition, the μ phase formed and serious separation occurred in the high entropy alloys. The content of μ phase increased with the increase in Mo content. The microstructure of the alloys changed from an initial single-phase face-center-cubic (FCC) solid solution structure (x = 0) to a hypoeutectic microstructure (x = 15), then to a full eutectic microstructure (x = 19), and finally to a hypereutectic microstructure (x = 25). Coherent interface between μ phase and FCC phase was observed. The (CoCuFeNi)81Mo19 alloy with fully eutectic microstructures exhibited the highest yield strength of 557 MPa and fracture strength of 767 MPa in tensile tests at room temperature. The fracture surface revealed that the formation of great amounts of the μ phase resulted in the loss of ductility of (CoCuFeNi)100-xMox alloys.


2020 ◽  
Vol 6 (12) ◽  
pp. 1265e2
Author(s):  
Shuai Wang ◽  
Yuhong Zhao ◽  
Peng Cheng ◽  
Qingwei Guo ◽  
Xiaotao Xu ◽  
...  

2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li

A series of refractory high-entropy alloys VTaTiMoAlx with x=0,0.2,0.6,1.0 were designed and produced by vacuum arc melting. The effect of added Al elements on the microstructure and mechanical properties of refractory high-entropy alloys were investigated. The X-ray diffraction results showed that all the high-entropy alloys consist of simple BCC solid solution. SEM indicated that the microstructure of VTaTiMoAlx changes from equiaxial dendritic-like structure to typical dendrite structure with the addition of Al element. The composition of different regions in the alloys are obtained by energy dispersive spectroscopy and shows that Ta, Mo elements are enriched in the dendrite areas, and Al, Ti, V are enriched in inter-dendrite areas. The yield strength and compress strain reach maximum (σ0.2=1221MPa, ε=9.91%) at x=0, and decrease with the addition of Al element at room temperature. Vickers hardness of the alloys improves as the Al addition.


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