Fabrication,Microstructure And Properties Of Tantalum Tungsten Alloy

The valence electron structures of Ta-W alloy solid solutions with different W contents were analyzed according to the theory of solid and molecule electronic theory,the BLD method and the average atomic model.The number of covalent electron n_A,intensity factor?and bond energy Ea,the relationship between the valence electron structure parameters and macroscopic physical properties of Ta-W alloy were analyzed.Based on the valence electron theory,Ta-W alloy samples with different W contents were prepared by SPS sintering method.The microstructure of Ta-W alloy samples was analyzed by X-ray diffraction?XRD?,optical microscope?OM?,scanning electron microscopy?SEM?and electron microscopy.The density,hardness,flexural strength,tensile strength at room temperature were tested to study the effect of W content on the microstructure and properties of Ta-based alloys.In order to further explore the potential properties of Ta-based alloys,the microstructure and properties of Ta-W alloys were investigated by adding different amounts of Y₂O_3.The influence of different W content on the valence electron structure of Ta-W alloy was studied.The covalent electron number n_A,intensity factor?and bond energy Ea of the strongest bond were calculated.The valence electron structure parameters??,n_A?The relationship between strength and hardness.The results show that with the increase of W content,both?and n_A increase,and the strength and hardness of the alloy increase.The maximum value of hardness is obtained when the content of W is 50wt.%.After the discharge plasma sintering prepared Ta-W alloy samples,the results from X-ray diffraction show that W has been most solid solution to the Ta.And W content increases,the diffraction peak shifted to the right.The microstructure,fracture structure and EDS analysis of the alloy showed that the addition of W refined the grain,reduced the plasticity of the alloy,and the appearance of the W-like structure.The density and mechanical properties of Ta-W alloys with different W content show that the density decreases and the hardness increases gradually with the increasing addition of W.The flexural strength has a maximum value of 996.4 MPa when the content of W is2.5wt.%.And a tensile strength has a maximum value of 749.22 MPa when the content of W is 5wt.%Appropriate addition of Y₂O₃ can promote the densification and grain refinement of Ta-W alloy.The maximum density is 94.89%when the content of Y₂O₃ is 0.3wt.%.With the increase of Y₂O₃ content,the hardness,flexural strength and tensile strength of the alloy firstly increase and then decrease.When the content of Y₂O₃ is 0.3wt.%,the hardness and strength are both the maximum value.Y₂O₃ can improve the properties of the material through dispersion strengthening,and Y₂O₃ can improve the plasticity of Ta-W alloy.