Influence of alumina whisker or nano-carbon contents on the microstructure and mechanical properties of CuZrTiAlNi refractory high entropy alloy composites

2020 ◽  
Vol 62 (7) ◽  
pp. 678-688
Author(s):  
X. Jiang ◽  
J. Chen ◽  
H. Sun ◽  
Z. Shao
Keyword(s):  
Mechanical Properties ◽  
Load Transfer ◽  
Microwave Sintering ◽  
Fracture Morphology ◽  
Strengthening Mechanism ◽  
Cold Isostatic Pressing ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Structure And Property ◽  
Fine Grain

Abstract High-entropy alloy composites were fabricated by ball milling, cold isostatic pressing and microwave sintering to which were added varied contents of Al2O3 whiskers, La-Ce, and carbon nanotubes-graphene, respectively. The structure and mechanical properties of the composites were investigated by X-ray diffraction, scanning electron microscopy and a microhardness tester. The high-entropy alloy and composites show amorphous phases and some crystalline phases. Accordingly, the addition of the reinforcement phase can refine the grain size. The formation mechanism of the phase is mainly related to the factors of mixing entropy, enthalpy, differences in atomic size, and the structure and property of the elements. The hardness of the composites is higher than that of the alloy (437.5 HV), and those composites reinforced by 0.5 wt.-% nanotubes- 0.5 wt.-% graphene are the highest (593.99 HV). The fracture morphology of the Al2O3 whisker reinforced composite shows a river pattern, indicating brittle cleavage. According to the research results, it can be concluded that the strengthening mechanism of the high entropy alloy composites mainly reflects fine grain strengthening and load transfer, and the toughening mechanism mainly crack bridging and a pulling out of the reinforcing phase.

Microstructure evolution, mechanical properties and strengthening mechanism of refractory high-entropy alloy matrix composites with addition of TaC

2019 ◽  
Vol 777 ◽  
pp. 1168-1175 ◽  
Author(s):  
Qinqin Wei ◽  
Qiang Shen ◽  
Jian Zhang ◽  
Yin Zhang ◽  
Guoqiang Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Strengthening Mechanism ◽  
High Entropy Alloy ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
High Entropy

scholarly journals Microstructure and Mechanical Property Evolution during Annealing of a Cold-Rolled Metastable Powder Metallurgy High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (9) ◽  
pp. 833 ◽  
Author(s):  
Li ◽  
Qiu ◽  
Guo ◽  
Liu ◽  
Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Tensile Strength ◽  
Powder Metallurgy ◽  
Cold Deformation ◽  
Precipitation Strengthening ◽  
High Entropy Alloy ◽  
Σ Phase ◽  
High Entropy ◽  
Fine Grain

Precipitation strengthening is an effective approach to strengthen high-entropy alloys (HEAs) with a simple face-center-cubic (FCC) structure. In this work, CoCrFeNiMo0.2 HEAs were prepared by powder metallurgy, followed by cool rolling and subsequent heat-treatment at different temperatures. The effects of cold working and annealing on microstructure and mechanical properties have been investigated. Results show the fine and dispersed (Cr, Mo)-rich σ phase with a topologically close-packed structure precipitated in the FCC matrix after the prior cold deformation process, which enhanced the mechanical property of the CoCrFeNiMo0.2 alloy. The HEA annealed at 600 °C for 48 h had a tensile strength of 1.9 GPa but an elongation which decreased to 8%. The HEA annealed at 800 °C for 12 h exhibited a tensile strength of 1.2 GPa and an elongation of 31%. These outstanding mechanical properties can be attributed to precipitation strengthening and fine-grain strengthening.

scholarly journals Structure and toughening mechanical properties of multi principal component high entropy alloy

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4019-4025
Author(s):  
Junhao Dai
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Principal Component ◽  
Alloy System ◽  
Strengthening Mechanism ◽  
High Entropy Alloy ◽  
Toughening Mechanism ◽  
High Entropy ◽  
Specific Strength ◽  
Deformation Ability

At present, the strength and toughening degree of the multi-principal element high entropy alloy are not high, and the plastic deformation capacity is poor. In order to solve this problem, the structure and mechanical properties of the multi-element high entropy alloy were studied. The micro-structure and strengthening mechanism of the alloy were studied. By establishing a reliable random solid solution model and using the first principle to calculate the phase structure, thermodynamics, and elastic properties of the alloy, theoretical guidance is provided for the design and development of new high entropy alloy. The high entropy alloy system with high specific strength and high tensile plasticity was prepared, and its strengthening and toughening mechanism was studied. The experimental results show that with the increase of Zr content, the fracture strength of multi-component high entropy alloy first increases and then decreases. When it reaches a fixed value, the comprehensive mechanical properties of the alloy are the best. Compared with the two literature methods, the tensile strength of this method is 250 MPa, and the work hardening after yielding makes the alloy have higher strength and better plastic deformation ability.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

The effect of Cu and Mn elements on the mechanical properties of single-crystal CoCrFeNi-based high-entropy alloy under nanoindentation

2021 ◽  
Vol 129 (19) ◽  
pp. 195104
Author(s):  
Yuming Qi ◽  
Tengwu He ◽  
Miaolin Feng
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals Tribological and Mechanical Properties of Multicomponent CrVTiNbZr(N) Coatings

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Yin-Yu Chang ◽  
Cheng-Hsi Chung
Keyword(s):  
Mechanical Properties ◽  
Nitrogen Content ◽  
Adhesion Strength ◽  
Mechanical Performance ◽  
Bulk Material ◽  
High Entropy Alloy ◽  
Composition Gradient ◽  
Multilayered Structures ◽  
High Entropy ◽  
Alloy Target

Multi-element material coating systems have received much attention for improving the mechanical performance in industry. However, they are still focused on ternary systems and seldom beyond quaternary ones. High entropy alloy (HEA) bulk material and thin films are systems that are each comprised of at least five principal metal elements in equally matched proportions, and some of them are found possessing much higher strength than traditional alloys. In this study, CrVTiNbZr high entropy alloy and nitrogen contained CrVTiNbZr(N) nitride coatings were synthesized using high ionization cathodic-arc deposition. A chromium-vanadium alloy target, a titanium-niobium alloy target and a pure zirconium target were used for the deposition. By controlling the nitrogen content and cathode current, the CrNbTiVZr(N) coating with gradient or multilayered composition control possessed different microstructures and mechanical properties. The effect of the nitrogen content on the chemical composition, microstructure and mechanical properties of the CrVTiNbZr(N) coatings was investigated. Compact columnar microstructure was obtained for the synthesized CrVTiNbZr(N) coatings. The CrVTiNbZrN coating (HEAN-N165), which was deposited with nitrogen flow rate of 165 standard cubic centimeters per minute (sccm), exhibited slightly blurred columnar and multilayered structures containing CrVN, TiNbN and ZrN. The design of multilayered CrVTiNbZrN coatings showed good adhesion strength. Improvement of adhesion strength was obtained with composition-gradient interlayers. The CrVTiNbZrN coating with nitrogen content higher than 50 at.% possessed the highest hardness (25.2 GPa) and the resistance to plastic deformation H3/E*2 (0.2 GPa) value, and therefore the lowest wear rate was obtained because of high abrasion wear resistance.

Mechanical properties and microstructure of the Al0.3CoCrFeNiTi0.3 high entropy alloy under dynamic compression

2021 ◽  
Vol 812 ◽  
pp. 141147
Author(s):  
Xianzhe Zhong ◽  
Qingming Zhang ◽  
Jing Xie ◽  
Mingze Wu ◽  
Fuqing Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dynamic Compression ◽  
High Entropy Alloy ◽  
High Entropy

Microstructure and mechanical properties of the brazed region in the AlCoCrFeNi high-entropy alloy and FGH98 superalloy joint

2021 ◽  
Vol 804 ◽  
pp. 140714
Author(s):  
Shiwei Li ◽  
Jinglong Li ◽  
Junmiao Shi ◽  
Yajie Du ◽  
Yu Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Microstructure And Mechanical Properties
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