Theoretical Study On Al_1.5CrFeMnTi High Entropy Alloys With DFT Method

High-entropy alloys have excellent mechanical properties,wear resistance and corrosion resistance,and have become a research hotspot in the field of metal materials in recent years.Aluminum-containing high-entropy alloys are a common research object,but there are still many unclear points about its related theoretical mechanism,and it is difficult to obtain comprehensive and effective information only by relying on experimental methods.Therefore,this paper adopts the first-principles simulation calculation method based on density functional theory(DFT)to theoretically analyze the lattice structure,mechanical properties,phase stability,and high-pressure properties of Al_xCrFeMnTi(x=0?2)series high-entropy alloys.Research and clarify the influence law,change trend and related theoretical mechanism of aluminum content and alloy element composition on the properties of high-entropy alloys.The main research contents and conclusions of this paper are as follows:(1)By calculating the structural properties of Al_xCrFeMnTi high-entropy alloys,it is found that the lattice constants and densities of different component alloys are quite different,indicating that the types of alloy elements will have a certain impact on the structure of the alloy,but different elements bring The influence law of is not the same;under the BCC crystal structure,when the Al element content is in the range of 0?1.5 mol,the lattice constant of Al_xCrFeMnTi alloy increases with the increase of Al element content,and the density increases with the increase of Al element content.Decrease.The influence of FCC crystal structure is more complicated.(2)The total ground state energy and the formation enthalpy of the Al_xCrFeMnTi high-entropy alloy are calculated.The formation enthalpy determines the thermodynamic stability of the high-entropy alloy.Within the tested Al element molar content range,as the Al element molar content increases,the thermodynamic stability of the alloy gradually increases;under the same Al element molar content,the thermodynamic stability of the alloy with the BCC crystal structure is more stable than that of the FCC structure.(3)Judge the mechanical stability,ductility,ductility and brittleness of the alloy by calculating parameters such as elastic constant,Young's modulus,bulk elastic modulus,and shear modulus.The results showed that the Al_1.5CrFeMnTi high-entropy alloy with BCC structure is an ideal alloy that meets the design premise of light-weight and high-hardness alloys under normal temperature and pressure.It exhibits different toughness and brittleness under different judgment criteria.(4)The phase stability of the Al_1.5CrFeMnTi high-entropy alloy under high pressure was calculated,and the results found that in the high-pressure range of 0-50 GPa,the Al_1.5CrFeMnTi high-entropy alloy always exists in a stable BCC structure without phase transformation.As the pressure increases,the mechanical properties of the alloy have a certain impact between 20 GPa and 35 GPa,but the impact is limited.