Preparation By Electro-spark Deposition And Design Of W-Cu Functionally Graded Material

W-Cu functional gradient materials(FGM).have been widely used in the fields of aerospace,military equipment and nuclear reactors because of their high melting point,high sputtering threshold,ablation resistance and thermal shock resistance.However,series of problems exist in present,such as the complex preparation technology,the high cost and so on,which limit the use of W-Cu FGM.So it is deeply meaningful to develop a new preparation technology for the purpose of simplification,convenience and low cost.Therefore,the influence of layer thickness and composition on the temperature and stress field of W-Cu functional gradient materials was simulated by using ANSYS software.Besides,the interface bonding of W-Cu was analyzed by using MaterialStudio software.Based on above results,W-Cu FGM was prepared and the performance of the material was evaluated.The simulation results of temperature field and stress field show that,with the increase of design layers,the temperature gradient in the Y direction of the middle section becomes larger and the heat affected zone becomes narrower.The stress analysis of the interface's midpoint between the matrix and the sedimentary layer indicates that the stress changed from tensile stress with single layer to compressive stress with 4 layers.With the single layer thickness increase,the temperature gradient becomes more uniform.Besides,the value and area of the compressive stress obviously increased,When the thickness of the single layer is 0.3mm,the compressive stress at the midpoint of the interface between matrix and the sedimentary layer reaches 315MPa.From the above simulation results,we can conclude that the gradient design layer and single layer thickness need to be paid more attention during the actual preparation of W-Cu FGM.Based on the simulation results,the relationship between the position of the torch,the diameter of the electrode and the quality of the coating was analyzed.The W-Cu functionally graded materials prepared by electro-spark deposition(ESD)were evaluated.The results show that the surface morphology is better with 3mm diameter electrode and 75o torch angle than others,and the roughness improved as the deposition passes increase.Besides,With the increase of the number of Gradient layers and the thickness of the single layer,the gradient feature of the gradient material along the thickness direction becomes more obvious.When the thickness of the single layer is 0.3mm,the gradient feature of the element distribution and properties becomes most obvious of all.However,W-Cu segregation phenomenon and some holes exist inside the W-Cu functionally graded materials.The analysis of the matching and bonding properties of the W-Cu interface indicates that W-Cu is difficult to bond when combined directly with poor bonding property,the adhesive work is only J/m2.Based on the calculation and experimental results,W-Cu FGMs were prepared by electro-spark deposition,which provide a new technological methods for the design and preparation of FGM.