Simulation And Heat Treatment Process Of Selective Laser Melting Forming For Inconel 625

Selective Laser Melting(SLM)is an important branch of Additive Manufacturing.Its principle is that the three-dimensional models of partare parsed and divided into several contour layers.Finally,the parts are formed by melting and stacking layer by layer with high-energy laser at one time.It is one of the focuses in the field of material forming in recent years.Inconel 625 nickelbased superalloy has been used as a key part of aerospace equipment due to its excellent high temperature mechanical properties and oxidation resistance.SLM of Inconel 625 combines the rapid prototyping of SLM technology and the good high temperature properties of Inconel 625,which can make Inconel 625 material have a broader application prospect in other fields in the future,and is also the future development trend of other nickel-based superalloys.The SLM forming process of Inconel 625 was simulated by finite element method which based on COMSOL Multiphysics.In the process of SLM forming,the process parameters have great influence on the performance of the forming parts.Firstly,the algorithm of laser source is improved,and the reflection of laser between metal powder particles is considered,which makes the light source model more precise.Thermal conductivity model and metal powder layer model were added to simulate the temperature and stress distribution of Inconel 625 powder in SLM forming process.By analyzing the influences of laser power,scanning distance and scanning speed on temperature field and stress field,the performance of Inconel 625 parts by SLM was improved by optimizing the processing parameters.By simulating the instantaneous stress field of parts in the process of forming,it can be seen that a large number of thermal stresses will occur in the process of SLM.After processing,these thermal stresses will be transformed into residual stresses,which will have a negative impact on dimensional stability and service life of parts.Using of solid solution and aging heat treatment methods can reduce the residual stress of parts.After the change of mechanical properties and microstructure changes to develop heat treatment plan through experimental analysis of heat treatment for further improving the performance of SLM formed Inconel 625 alloy parts.Finally,This research has a certain reference value for the heat treatment process formulation of SLM forming parts of other nickelbased superalloys.