Mechanical Behavior of Novel Suction Cast Ti-Cu-Fe-Co-Ni High Entropy Alloys

2014 ◽  
Vol 790-791 ◽  
pp. 503-508 ◽  
Author(s):  
Sumanta Samal ◽  
Sutanuka Mohanty ◽  
Ajit Kumar Misra ◽  
Krishanu Biswas ◽  
B. Govind
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
The Novel ◽  
Electron Microscopic ◽  
High Entropy ◽  
Alloy Chemistry ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Ductile Mode

The present investigation reports mechanical properties of novel multicomponent TixCuyFe20Co20Ni20 high entropy alloys (HEAs) with different alloy chemistry (x/y = 1/3, 3/7, 3/5, 9/11, 1, 11/9 and 3/2). The alloy cylinders were prepared by vacuum arc melting-cum-suction casting route. The detailed electron microscopic observations reveal the presence of three different solid solution phases; FCC (a1) phase, FCC (a2) phase and BCC (b) phase for all the investigated alloys, whereas ultrafine eutectic between FCC (a1) phase, and Ti2 (Co, Ni) - type Laves phase has been observed for the HEAs with x/y = 9/11, 1, 11/9 and 3/2. Room temperature compression test of the suction cast cylinders with aspect ratio of 2/1 has been conducted to obtain mechanical properties of the HEAs. The optimum combination of strength (~ 1.88 GPa) and plasticity (~ 21 %) is obtained for x/y = 9/11; indicating simultaneous improvement of strength as well as plasticity of the novel HEAs. Fractographic analysis of the fractured surfaces reveals mixed mode of fracture for x/y = 1/3, 3/7 and 3/5, ductile mode for x/y = 9/11 and 1, whereas brittle mode of fracture for x/y = 11/9 and 3/2.

Microstructure and Mechanical Properties of VTaTiMoAlx Refractory High Entropy Alloys

2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
Dendrite Structure ◽  
X Ray ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Microstructure And Mechanical Properties

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.

scholarly journals A Novel Low-Activation VCrFeTaxWx (x = 0.1, 0.2, 0.3, 0.4, and 1) High-Entropy Alloys with Excellent Heat-Softening Resistance

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 951 ◽  
Author(s):  
Weiran Zhang ◽  
Peter Liaw ◽  
Yong Zhang
Keyword(s):  
Vickers Hardness ◽  
Vacuum Arc ◽  
Compressive Yield Strength ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Structural Applications ◽  
Typical Morphology ◽  
Bcc Phase

The microstructure, Vickers hardness, and compressive properties of novel low-activation VCrFeTaxWx (x = 0.1, 0.2, 0.3, 0.4, and 1) high-entropy alloys (HEAs) were studied. The alloys were fabricated by vacuum-arc melting and the characteristics of these alloys were explored. The microstructures of all the alloys exhibited a typical morphology of dendritic and eutectic structures. The VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys are essentially single phase, consisting of a disordered body-centered-cubic (BCC) phase, whereas the VCrFeTa0.2W0.2 alloy contains fine, nanoscale precipitates distributed in the BCC matrix. The lattice parameters and compositions of the identified phases were investigated. The alloys have Vickers hardness values ranging from 546 HV0.2 to 1135 HV0.2 with the x ranging from 0.1 to 1, respectively. The VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys exhibit compressive yield strengths of 1341 MPa and 1742 MPa, with compressive plastic strains of 42.2% and 35.7%, respectively. VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys have excellent hardness after annealing for 25 h at 600–1000 °C, and presented compressive yield strength exceeding 1000 MPa with excellent heat-softening resistance at 600–800 °C. By applying the HEA criteria, Ta and W additions into the VCrFeTaW are proposed as a family of candidate materials for fusion reactors and high-temperature structural applications.

Microstructure and Mechanical Properties of the W-Ni-Co System Refractory High-Entropy Alloys

2015 ◽  
Vol 816 ◽  
pp. 324-329 ◽  
Author(s):  
Hui Jiang ◽  
Li Jiang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Melting Temperatures ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

Microstructure and Properties of Multi-Component AlxCoCrFeNiTi0.5 High-Entropy Alloys

2013 ◽  
Vol 745-746 ◽  
pp. 775-780 ◽  
Author(s):  
Yong Dong ◽  
Yi Ping Lu ◽  
Jun Jia Zhang ◽  
Ting Ju Li
Keyword(s):  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Test Results ◽  
High Entropy ◽  
Solid Solution Strengthening ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Solution Strengthening ◽  
Bcc Phase

The multi-component AlxCoCrFeNiTi0.5 (x=0, 0.2, 0.5, 0.8, 1.0) high-entropy alloys were prepared by vacuum arc melting. The microstructure and mechanical properties were studied. It was found that the structure transformed from FCC into FCC + BCC + Laves, and finally into BCC with the increase of Al content. The compress test results showed that with the addition of aluminium from 0 to 1.0, the fraction strength increased while plasticity reduced. In the stain rates of 5×10-3/s and 1×10-3/s, when x=0.8 the fraction strength achieved maximum and x=0 the plastic was best, the strength of 2879MPa and 2433MPa, the strain of 0.21 and 0.22, respectively. The hardness increased obviously (from Hv479.1 to Hv692.7) when Bcc phase and Laves phase appeared. The analysis revealed that the strengthen mechanism was mainly composed of solid solution strengthening and precipitation strengthening.

scholarly journals Examination of Fracture Mechanisms in two Al – Ti – V – Cr – (Si) High Entropy Alloys

2021 ◽  
Vol 349 ◽  
pp. 02002
Author(s):  
Spyridon Chaskis ◽  
Dimitrios Kiousis ◽  
Pavlos Stavroulakis ◽  
Russell Goodall ◽  
Spyros Papaefthymiou
Keyword(s):  
Sem Analysis ◽  
Vacuum Arc ◽  
Fracture Mechanisms ◽  
High Entropy Alloys ◽  
Dendritic Microstructure ◽  
Slow Cooling ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Bcc Phase

This work focuses on the examination of two High Entropy Alloys (HEAs), the AlTiVCr and AlTiVCr–Si7.2, which have been observed to fail in a brittle manner directly after casting. Understanding the failure mechanics is a prerequisite for an alternative enhanced alloy design in order to prevent early failure without loading application. The specimens were produced using the Vacuum Arc Melting methodology in a protective argon atmosphere. The material was re–melted five times in combination with electromagnetic stirring in order to achieve a fully homogenized microstructure. Based on our findings, the failure occurred in the first 10 minutes after casting during slow cooling. Similarly, the same took place during thermal treatment after the third re–melting. The specimens were first prepared for optical (OM) and scanning electron microscopy (SEM) analysis. The material consists of a coarse dendritic microstructure as well as a retained BCC phase, which is the AlTiVCr phase. In the AlTiVCr – Si7.2 alloy a uniformly dispersed, angular intermetallic compound, namely the Ti5Si3, was identified, which increases the failure resistance of the material. Based on these findings the alloy will be redesigned.

Effect of silicon addition on alcocrfeni high entropy alloys prepared by vacuum arc melting

2020 ◽  
Author(s):  
Anil Kumar ◽  
Arun Arora ◽  
Rituraj Chandrake ◽  
K. Raja Rao ◽  
Manoj Chopkar
Keyword(s):  
Vacuum Arc ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Silicon Addition

Microstructure of Nb-Ta-V Based Hydrogen Permeation High Entropy Alloys

2016 ◽  
Vol 849 ◽  
pp. 3-7 ◽  
Author(s):  
Nai Juan Wang ◽  
Yuan Liu
Keyword(s):  
Hydrogen Permeation ◽  
Hydrogen Permeability ◽  
Dendritic Structure ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Body Centered Cubic ◽  
X Ray ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting

High-entropy alloys of NbTaVTiNi, NbTaVTiCo, NbTaVHfCo, NbTaVHfNi, and NbTaVZrNi were synthesized by vacuum arc melting. The crystal structure was identified by an X-ray diffractometer analysis. Microstructures and element composition of the resulting alloys were investigated using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. All alloys presented the dendritic structure which is mainly composed of body-centered cubic (NbTaV,X) (X=Ti, Hf, Zr) phases and eutectic-like phases such as TiNi, TiCo, HfCo, HfNi and ZrNi. (NbTaV,X) phases take the function of hydrogen permeability while eutectic-like phases bear the responsibility of resistance to hydrogen embrittlement. Taking the microstructure of alloys into account, NbTaV-based high entropy alloys is appropriate for improving hydrogen permeability.

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