Elastic Properties Of High Entropy Alloys By MaxEnt Approach

High-entropy alloys(HEAs)are a new type of alloys,which have subverted the method of preparing alloys for thousands of years.The development of HE As has a history of 14 years,but the experimental and theoretical studies related to HEAs were reported more in 2013.Therefore,the field of HEAs is in the stage of rapid development,which needs more research and exploration.The concept of HEAs is novel and their properties are excellent,so HEA has gradually attracted the interest of researchers.The main characteristic of HEAs is that they contain four or more metal elements.Because it contains more than four elements,thousands of HEAs can be arranged and assembled by changing elements and concentrations.Therefore,it takes a lot of time and resources to screen HEAs and get better components by experimental research.The first-principles calculation has high efficiency and can provide reliable data for the study of materials.Therefore,the properties of HEAs are studied by first-principles calculation in this work.However,compared with conventional alloys,it is harder to study HEAs by first-principles calculation,because of the complexity of HEAs and the processing ability of computers at the moment.Some properties are computable for conventional alloys,however,particularly difficult for HEAs.The method of establishing atomic models of HEAs is not mature,and there is no data to prove which model is more accurate or suitable for studying HEAs.In this work,a new model is proposed,and the elastic properties of HEAs are calculated.The work is as follows:Firstly,atomic structure models of dozens of HEAs were established by using maximum entropy model.The HEAs are divided into five kinds,and the generation process of MaxEnt structures of them is described.The consistency of the model is calculated.Secondly,based on the MaxEnt model,the elastic properties of HEAs with body-centered,face-centered and hexagonal structures are calculated by the first-principles calculation.The elastic properties of dozens of HEAs were calculated.In order to verify the accuracy of the model,the theoretical values of TaNbHfZrTi(elastic properties have experimental values)are calculated and compared with the existing experimental values.At the same time,the elastic properties calculated by MaxEnt and EMTO-CPA methods are compared,and the differences between the two methods are analyzed.The effect of lattice distortion on the calculation results of elastic properties is discussed.Because MaxEnt is a supercell model,it can also be used to simulate HEAs with complex ratios.In addition,the effects of Al,Fe,Ti,Cu and Mo on the elastic properties of HEAs are analyzed.The effects of magnetic spin and periodic boundary conditions on the calculated results are studied.Finally,in order to reduce the low-temperature brittleness of HEAs VMoNbTaW,the effect of element concentrations on the elastic properties of V-Mo-Nb-Ta-W system was studied,reducing low temperature brittleness while minimizing alloy density.Therefore,based on the MaxEnt,the effect of element concentrations on the elastic properties of V-Mo-Nb-Ta-W system is studied and analyzed,which can guide the experimental study of V-Mo-Nb-Ta-W system.