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Research Of WC-12Co Coat Interface And Numerical Simulation And Analysis Of Temperature Field And Stress Field For Electrospark Deposition

Posted on:2014-09-11Degree:MasterType:Thesis
Country:ChinaCandidate:C HanFull Text:PDF
GTID:2251330422951021Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
Electrospark deposition is an important surface strengthening technology, its has little heat effect on the substate and high coating bonding strength, It is flexible to operate, In the preparation of high-performance coatings more advantages than traditional methods on the surface of Parts. In this paper, we used Electrospark deposition method implements WC-12Co deposited cermet coating on the surface of TC4alloy. And in accordance with the mechanism of spark discharge established finite element model for TC4substrate electrode and WC-12Co tool electrode single pulse temperature field, And established temperature field and stress field model on the birth and death element.For WC-12Co coatings characterized by scanning electron microscopy, optical microscopy, spectroscopy, micro hardness tester, and other analytical tools explain WC-12Co coating interface morphology. Describes the single pulse deposition point "pit spring" feature, and the point of deposition typical elements of the content area were compared and found that the coating Ti content is higher. Microhardness tester using the coating hardness of the regions found that the transition region is higher than the hardness of the coating and substrate. Study the relationship between the thicknesses of deposited layers and found that, with the deposition of layers increases, the growth rate gradually decreased thickness, there is a limit to the thickness of the coating.Using ANSYS finite element software for single-pulse temperature field analysis, by selecting the Gaussian heat to study the temperature field distribution over time, due to thermophysical properties of different materials, the shape is not the same temperature field by setting the temperature field contour can be determined electrode material melting and vaporization area size, the study found gasification process parameters on the melting and regional influence, simulation results and validation tests found the peak current is20A, the pulse period of240μs; it can get a better deposition morphology.Through the heat-structure coupling units to solve the model to obtain Electrospark deposition coating temperature field and stress field distribution. Along the surface and the depth, the analysis for the thermal stress distribution and the change prove X direction of the tensile stress in a larger contribution to the total. Combined with deposition of the coating during cooling at room temperature, the residual stress formation and variation are discussed and studied the process parameters on residual stress, provide a reference for the cases to reduce the residual stress and avoid coating cracks.
Keywords/Search Tags:electrospark deposition, interface morphology, finite element simulation, residual stress
PDF Full Text Request
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