The Synergistic Effect of La₂O₃ and Y₂O₃ on the Microstructure and Mechanical Properties of Fe/FeAl₂O₄ Cermets AITranslate

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Chinese Library Classification Number:TG148[一般工业技术]

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Due to the insufficient understanding of the mechanism behind rare earth synergistic strengthening in cermets,this study systematically investigated the coupled effects of La₂O₃ and Y₂O₃ co-doping on the microstructure and mechanical properties of Fe/FeAl₂O₄ cermets using X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM)and electron probe microanalysis(EPMA).The results indicate that La³⁺preferentially forms a solid solution in the FeAl₂O₄ lattice,while Y³⁺mainly enriches at grain boundaries to form a glass network structure.When the mass fractions of La₂O₃ and Y₂O₃ reach 0.2%and 0.5%,respectively,the average grain size of the FeAl₂O₄ phase decreases from 28.56 nm to 27.03 nm,compared with that without rare earth doping.At this point,the material exhibits optimal comprehensive properties:relative density is 99.96%,Vickers hardness is 3766 HV,and bending strength reaches 138.9 MPa,representing improvements of 4.1%,12.3%and 18.6%,respectively,compared with the sample without rare earth doping.Mechanism analysis indicates that the synergistic effect of dual rare earths promotes the in situ formation of La-Y-Si-O composite silicates,and the rod-shaped microcrystals of the La-Y-Si-O phase suppress grain coarsening through pinning effects and increase the relative density,thereby enhancing the mechanical properties.This study provides a new design strategy for rare earthmodified cermets.