Fabrication And Properties Of W-high Entropy Alloy

High entropy alloys（HEAs）are a new effort in materials science and engineering and can possess special properties.These include high strength/hardness,exceptional high-temperature strength,good corrosion and oxidation resistance.So HEAs are being considered for a wide range of functional and structural applications in the transportation,aerospace and military industry.In this paper,the powder of Al_0.6CoCrFeNi was synthesis through high pressure gas atomization.Then,selecting the appropriate particle size of the powder which is mixed with tungsten powder.Tungsten heavy alloy prepared by liquid-phase sintering method.Microstructure and mechanical properties have been investigated.The major results can be summarized as follow:The powder of Al_0.6CoCrFeNi were synthesis successfully via to high pressure gas atomization.Powder median particle size distribution is associated with the degree of superheat,atomization pressure and draft tube diameter.The morphology of powder is spherical.As the powder particle size decreases,the phase composition of powder gradually transformed into single-phase structure,the microstructure of powder transformed into dendrite,cellular and equiaxed crystal alloy,the liquids temperature of the powder is constant.The cooling rate of the powder is calculated by gas atomization model.It found that the cooling rate of powder is between 10⁴K/s¹0⁶K/s,the solidification process of alloy is much deviation from equilibrium state.The degree of solidification process deviating from equilibrium state at different from cooling rates is the main cause of the powder phase composition and microstructure.We obtain a corresponding relationship between the powder particle size,cooling rate,phase composition and microstructure.Tungsten heavy alloy were prepared by liquid-phase sintering.It found that there are diffusion reaction zone between tungsten particles and boded phases,Cr-rich is existed at the interface between the tungsten particles,the fracture strength of alloy increased,the ductility and formability is reduced.Combined with good plasticity characteristics of Ni,Ni element was added to the binder phase,W-Ni-HEA was prepared.Compared with W-HEA,fracture strength and ductility of the alloy are significantly increased.