Microstructures And Properties Of High Entropy Alloys Containing Magnesium

The design of the alloy has been shackled by the traditional design concept,but the traditional alloys are becoming more and more difficult to meet the needs of production and life.As a new kind of alloy material,high entropy alloy has many excellent properties.Meanwhile,magnesium is widely studied as a light hydrogen storage material,but its hydrogen storage performance is inadequacies,and alloying is an important method to improve its hydrogen storage performance.With the design concept of high entropy alloy,high entropy alloy containing magnesium was prepared by mechanical alloying.The microstructure and phase structure of the alloy were analyzed by X-ray Diffraction?XRD?and scanning electron microscope?SEM?.Thehydrogen storage properties,electrochemical properties,corrosion resistance and magnetic properties of the high entropy alloys containing magnesium were also studied.The obtained result are as follows:?1?The solid solution structure of BCC₁ structure appeared in the phase structure of Mg_1.7AlFeCuCr,Mg₂TiMFeNiCr?M=V,Al,Mn?,Mg₂Ti₂Vcu_0.5Ni_0.5Co,Mg₂TiVCuNiCr.Mg_1.7AlFeCuCr is a single phase BCC₁ structure,Mg₂Ti₂Vcu_0.5Ni_0.5Co is a dual phase structure?BCC₁+FCC?,and the other four alloy samples have no solid solution elements.Hydrogen absorption and desorption of Mg_1.7Al FeCuCr,Mg₂TiAlFeNiCr,Mg₂TiVFeNiCr,Mg₂TiVCuNiCr can be carried out at 300?,4 MPa.Of which Mg₂TiAlFeNi Cr maximum hydrogen absorption is 1.50 wt%.The hydrogen desorption pressure of the four alloys is higher than that of pure magnesium,indicating that the hydrogen desorption is more easy than pure magnesium.The electrochemical capacity of the alloy is low at 25?,the maximum capacity of Mg₂TiVFeNiCr is only 93.7 mAh/g,and the capacity is increased when the temperature is increased.The maximum capacitance of Mg₂TiVFeNiCr is 212.3mAh/g at 70?,but the electrochemical cycling stability of the alloy electrode is poor.?2?Theoretical calculation of the thermodynamic parameters of magnesium containing high entropy alloy Mg_xTiAlFeNiCr?x=0.6,0.8,1.0,1.2,1.4,1.6,1.8,2.0,2.2?indicatethat:whenx=0.6¹.4,thethermodynamicparameters:-14.13KJ/mol??H_mix?-6.76 KJ/mol,8.68%???9.77%,1.70???3.36,15.00%??35?R_max?17.50%.The alloy is single BCC₁ structure;when x=1.6¹.8,the thermodynamic parameters:-5.40KJ/mol??H_mix?-4.19KJ/mol,10.03%???10.15%,4.14???5.24,14.20%??R_max?14.70%,alloy is a dual phase BCC structure?BCC₁+BCC₂?;when x=2.0².2,thethermodynamicparameters:-3.10KJ/mol??H_mix?-2.13KJ/mol,10.23%???10.29%,6.95???9.92,13.30%??R_max?13.70%,the phase structure of the alloy is BCC₁+BCC₂+Mg,with the increase of the value of?H_mix,?,?,and the decrease of the value of?35?R_max,the alloy transition from single-phase structure to multiphase structure.The theoretical calculation results will provide a theoretical basis for the design of magnesium containing high entropy alloys;the corrosion resistance of high entropy alloy in 10%HCl solution and 3.5 wt%NaCl solution was studied:the corrosion resistance of the alloy gradually decreases with the increase of the content of magnesium,and the corrosion resistance of high entropy alloy is stronger than magnesium alloys in 3.5wt%NaCl solution;in addition,the magnetic properties of high entropy alloys show that the coercivity of alloy is between 10 Oe³00 Oe,which can be applied to semi hard magnetic alloy field.