Research On Preparation And Thermal Stability Of AlCrWTaTiNb High Entropy Alloy Films

With the introduction of high entropy concept in recent years,many high methods of entropy alloy preparation are developed to prepare high entropy alloy block materials.Due to the different density of alloying elements,the elements are segregated during the process of making bulk materials.Considering that high entropy alloys are mainly used to make high surface properties of materials,therefore,high-entropy alloy thin film materials are used as the research object.With the further development of high entropy alloys,the process of preparing high entropy alloy films is already mature.However,there are few studies on the subsequent heat treatment performance of the films.There is no intuitive comparison between the influences of film preparation process on the film properties and the influences of subsequent heat treatment process on the film properties.Because high-entropy alloy films are commonly used on high-temperature or high-speed running materials,this is equivalent to the heat treatment of high-entropy alloys,so the study of the thermal stability of high entropy alloys is very important.Based on the above exploration,high entropy alloy films were prepared by single target DC magnetron sputtering in this paper.The effects of substrate bias and substrate temperature on the composition,deposition rate,microstructure,surface morphology and mechanical properties of high entropy alloy films were investigated.The effects of different annealing temperatures on the composition,microstructure,surface morphology and mechanical properties of high entropy alloy films were also investigated.The results show that AlCrWTaTiNb has a certain performance at high temperature.The following conclusions are drawn from the experiments:1.Whether the substrate bias change or not,the substrate temperature during the film deposition or the heat treatment temperature after the film formation,the composition of the film always satisfies the definition of high entropy alloy.2.When the substrate bias voltage is increased,the content of each element in the alloy thin films is kept constant,but the deposition rate decreases,and the mechanical properties of the film increase first and then decrease.3.When the temperature of the film deposition is increased,the chemical composition of the films did not change significantly,the crystal structure did not have a big change,while the speed increases first and then declines.The mechanical system can also increase first,to reach the maximum,then it starts to fall.4.When the high entropy alloy film is annealed,the surface of the film undergoes obvious precipitation of intermetallic compounds.The mechanical properties of the films are gradually improved with the increase of the annealing temperature,and then the increase is gradually slowing down.