Study On Preparation And Mechancial Properties Of AlCoCrFeNiV High Entropy Alloys

It has attracted widespread attention since the concept of high entropy alloys?HEAs?or multi-principal alloys?MPEAs?were proposed.Many researchers have found that HEAs have very excellent properties,such as high strength,high hardness,good wear resistance,corrosion resistance,excellent oxidation resistance and unique magnetic properties.HEAs with more excellent and balanced performance can be obtained by properly adjusting the composition.In this paper,Al_0.5Cr_0.9FeNi_2.5V_X and AlCoCrFeNiV_X bulk HEAs with different vanadium content were prepared by non consumable vacuum arc furnace.The effect of vanadium content on the microstructure and phase of the alloys were investgated by XRD,SEM and EDS.The effect of vanadium element on its properties was explored by Vickers hardness tester and multi power testing machine,and comprehensively compare the difference in microstructure and properties of HEAs with different components.The results show that the non equimolar Al_0.5Cr_0.9FeNi_2.5V_X bulk HEA has a single-phase FCC structure,while the equimolar AlCoCrFeNiV_X bulk HEA has a single-phase BCC structure.These alloys all have different degree of lattice distortion,the microstructure of the alloys were refined,and the CrV phase with uniform distribution appeared in the structure,which significantly improved the properties of the alloy;Non-equimole alloys had lower strength,but the plasticity was better,and the wear mechanism was adhesive wear.Equimolar alloys had higher strength,but the plasticity was correspondingly worse.The wear mechanism was abrasive wear and oxidation wear.AlCo CrFeNiV_X HEA coatings were prepared by plasma spraying and laser remelting methods due to the AlCo Cr FeNiV_X bulk HEA with higher strength and better wear resistance.It was found that the alloy initially was FCC,with the addition of vanadium,and the structure gradually changed to BCC.The microstructure changed from dendrite to equiaxed crystal,and the acicular CrV phase appeared.With the addition of vanadium content,the microhardness of the alloy were increased.When the vanadium content was 1.0,the microhardness reached 627.43HV.The wear loss gradually decreased,indicating that wear resistance was also improved.The wear loss was 0.0258 g without vanadium addition.,and it was reduced to 0.0109 g when the vanadium content increased to 1.0.The wear mechanism abrasive wear with slight oxidation wear.