Research And Application Of Strengthening Mechanism Of Zirconium-yttrium Oxide Strengthening Platinum-rhodium Materials

Platinum-based high-temperature materials have been used in glass and glass fiber industry for more than one hundred years.With the development of social demand and glass fiber industry,the demand for platinum-based high-temperature materials is increasingly.The basic trend is to continuously strengthen platinum-based high-temperature materials through a variety of strengthening methods,so as to achieve higher performance of materials.In this study,the strengthening mechanism and application of a new type of zirconium yttrium oxide with good properties were studied.Paper using Optical metallography(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and creep experimental analysis means such as measuring instrument,as well as the First principles method,lattice inversion theory,molecular dynamics and finite element method,by experiments,and the combination of theoretical analysis and simulation research method to carry out research work.The main physical properties of a new type of zirconium yttrium composite oxide reinforced Pt Rh5 material and its high temperature mechanical properties and creep rate equation were determined.Resistance measurement method is used to solve the containing Zr Y was 0.2wt%Pt Rh5 alloy oxidation kinetics in the quantitative characterization method.Establish internal oxidation of oxygen diffusion calculation model.The formula of oxygen diffusion-resistance-time is derived theoretically,and calculated with the formula for the oxygen diffusion coefficient in the internal oxidation,internal oxidation of optimal time formula is given,and solves the key problem in the study of the oxidation of the material.Through the analysis of the experimental measurement and stereographic projection map,determine the creep fracture appear on hexagon is nearly related to the strengthening mechanism of organization of steps because:The cleavage plane formed by oxygen corrosion in high temperature atmosphere constitutes step structure,and crystal by{001}and{111}crystal form,the family nearly steps is hexagon material in the process of creep rupture Pt Rh5 alloy of{001}<110>and{111}<211>alternates between cleavage fracture,and the spiral extension after the formation of the special groups,and quantitative hexagon is nearly steps is given the organization a concrete example.TEM analysis shows that the larger size of the oxide formed by internal oxidation is mainly distributed in the grain boundary,while the smaller size of the oxide is distributed in the grain interior.The oxide was Zr O₂ with monocline structure,and the concentration of solid solution Y was less than 0.97%mol.Y could improve the mechanical properties of the composite oxide to some extent.Electron diffraction has found that there is a certain orientation relationship between the Pt Rh5 alloy matrix and the oxide interface,and there is a certain coherent and semi-coherent relationship,which is the experimental result that has never been obtained before.The results show that the coherent and semi coherent relationship on the interface provides a certain way and mechanism for the high temperature strengthening of the material,namely the interface strengthening mechanism,which is a newly discovered strengthening mechanism of the material.Theoretical analysis gives the possible relations and data of all interface orientations.Based on Density Functional Theory,Virtual Lattice Approximation method and Lattice Inversion Potential theory,the simulation of interface strengthening mechanism and microbehavior of zirconium yttrium oxide reinforced Pt Rh5 alloy was studied.The validity of Virtual Lattice Approximation method for Platinum-Rhodium alloy system was tested,and the inversion potential of pure Pt,pure Rh and Pt Rh5 alloys was constructed.A new high-precision potential function fitting formula with 5 parameters is proposed.Firstly,the lattice inversion potential functions of Zr O are constructed,and then inversion potential function of monoclinic Zr O₂ is constructed,and the results are verified by test.Then the interface inversion potential between the oxide and Pt Rh5 alloy was successfully constructed.These constructed inversion potentials were used in molecular dynamics simulation studies to determine that Pt Rh5 alloy atoms at the interface were more inclined to bond with Zr atoms.It is concluded that the diffusion rate of oxygen atoms in the alloy is the controlling factor of oxide growth in internal oxidation.The strengthening mechanisms of zirconium yttrium composite oxides in Pt Rh5 materials are determined as follows:the mechanical properties of oxides are improved,the second phase dispersion is strengthened,the grain boundary is strengthened,the interface is strengthened and so on.The strengthening effect is the comprehensive strengthening effect of various mechanisms.The interface strengthening mechanism of alloy matrix/oxide due to coherent and semi-coherent relationship is a new strengthening mechanism.Based on the thesis experiment measured the material data,using the Finite Element Method,quantitative research is the actual use bushing in the use of current field,stress and strain field in the process of the physical fields,as well as the creep behavior and so on characteristics,predicting the deformation characteristics of bushing,and the calculated results with measured results than meet,also suggests that use high performance materials.The research route and concrete implementation method from material property to bushing property prediction are realized.