Preparation And Mechanical Properties Of High Entropy Alloy Dispersion Strengthened FeCrAl Alloy

FeCrAl alloy has excellent high-temperature steam corrosion resistance,neutron radiation resistance and good processability,making it one of the most competitive candidate materials for advanced ATF cladding materials.However,as a cladding material for the core,low mechanical strength and poor neutron economy still limit the application of FeCrAl alloy.To this end,this article uses high entropy alloy as a dispersion strengthening phase and prepares high entropy alloy strengthened FeCrAl alloy by mechanical milling and spark plasma sintering.Through SEM,XRD,EBSD,TEM,density test,hardness analysis,tensile property test and other analysis methods,the influence of process parameters,types and content of high entropy alloy on microstructure and properties of FeCrAl alloy are systematically studied.The experimental conclusions are as follows:（1）By comparing two sets of Al_1.8CuCrFeNi₂-FeCrAl alloys with contents of 0%,2%,4%,6%and 8%,the effect of anhydrous ethanol as the process control agent was studied.The experimental results indicate that anhydrous ethanol will promote the formation of rich Cr-a’phase and nano Al₂O₃ particles.Its uneven distribution will weaken the plasticity of the alloy and reduce the structural stability of the alloy.Therefore,anhydrous ethanol is not suitable for use in scenarios of enhancing FeCrAl alloy with high content and high entropy alloy.In addition,by comparing the mechanical properties of 6%Al_1.8CuCrFeNi₂-FeCrAl alloy at different sintering temperatures,it was found that higher sintering temperature would increase the contact area between particles and reduce the generation of macroscopic defects,promote the diffusion rate of solid solution elements and eliminate the micro defects produced in the ball milling process.This is very helpful for the comprehensive mechanical properties of the alloy,so 1050℃is the best sintering temperature.（2）When the content of Al_1.8CuCrFeNi₂ high-entropy alloy is 6%,the room temperature mechanical properties of Al_1.8CuCrFeNi₂-FeCrAl alloy are the best:the ultimate tensile strength is 1358 MPa and the elongation is 14.9%.At the same time,its mechanical properties at 800℃are also the best:the ultimate tensile strength is 96MPa,and the elongation is 6.9%.However,when the content of Al_1.8CuCrFeNi₂ high-entropy alloy exceeds 15%,the mechanical properties of Al_1.8CuCrFeNi₂-FeCrAl alloy both at room temperature and high temperature show a serious decline.The tensile strength is not more than 20MPa.（3）When the content of Al_0.5CrFeNi_2.5Mo high entropy alloy is 25%,the room temperature mechanical properties of Al_0.5CrFeNi_2.5Mo-FeCrAl alloy are the best:the ultimate tensile strength is 1252MPa and the elongation is 5.2%;however,when the content of Al_0.5CrFeNi_2.5Mo high entropy alloy is 35%,Al_0.5CrFeNi_2.5Mo-FeCrAl alloy exhibits an extremely excellent mechanical properties at 800℃:the ultimate tensile strength is 145MPa and the elongation is 34.7%.