Research On Thermal Behavior Of Titanium Laser Deposition Repair Assited By Induction Heating

Laser deposition repair combines the advantages of laser deposition with rapid prototyping, having a controllable energy input, 3D rapid manufacturing, etc, in the aerospace, industrial, medical and other fields has achieved a wide range of applications. However, concentrated in the repair process has the energy input, rapid heating and cooling and other features,there is a large thermal stress between the specimen and the substrate, when the heat stress reaches the material limit, the specimen will crack or even break. Especially in the field of precious metals such as titanium alloy parts, due to the repair workpiece is in mechanical processing stage even finishing stage or service parts, machining allowance for little or no machining allowance, in order to prevent deformation and cracking, because of the small deformation will also destroy the integrity of the workpiece, therefore, the hard problem of deformation, crack is to be solved in the development and application of laser deposition repair.For the above problem, in this paper, using the method of induction heating to reduce TA15 laser deposition repair area temperature gradient in the process of repair, and research the effect of induction heating on laser deposition repair including organization, stress, hardness, etc by using the method of numerical simulation and experimental test. Specific methods are as follows:First, this paper aimed at the induction heating parameters-the different thickness of the substrate, preheating temperature, heating area of numerical simulation analysis was made on the influence of TA15 laser deposition repair process, and the surface temperature in laser deposition under induction heating was monitored and collected for real-time by using the infrared cameras, temperature distribution in different induction heating parameters was revealed; While the residual stress was tested by using indentation stress tester, the stress distribution and variation was revealed. A parameters optimization reference basis is provided for laser deposition repair assisted by induction heating from above analysis.Then, the induction heating preheating TA15 laser deposition repair experiments were carried out, deposition layer surface morphology, the size of weld width, height,microstructure, microhardness were studied, the influence of the microstructure and microhardness by induction heating preheating was revealed. the final validation of induction heating can effectively reduce the temperature gradient in the process of laser deposition repair and the thermal stress, and then to achieve control of deformation and cracking, improve the effect of deposition efficiency.In order to reduce the residual stress and deformation of the workpiece, the influence of the low energy input on the microstructure and residual stress was revealed by analyzing the surface morphology, melting width, high, microstructure, microhardness and residual stress of TA15 laser deposition repair which were got by low energy input. Analysis shows that: through the low energy input experiment, reasonable technological parameters are selected, To some extent, the purpose of controlling the performance of the workpiece is achieved.