Research On Numerical Simulation Of In-situ Mg₂Si/AM60Composites With Ultrasonic

In the21st century, with increasing global energy crisis, as well as the populartheory of sustainable development,Traditional heavy materials such as steel have beenreplaced by a good performance of various lightweight materials in many areas. Mgand Mg alloys play an important role in many areas such as outerspace, aerospace,marine vessels, diving equipment, electronic systems, automotive transportation.In the actual industrial production, filling and solidification process computersimulation of metal forming has an extremely important significance. Beforeproduction conducted simulation can effectively predict and defect analysis andcasting defects produced parts, so as to facilitate product design and structure of thecasting process design flexible correction, and for the production of high qualitycastings provides a wealth of reference data. This shortens the other hand, newproduct development and production cycles, compared with the traditional casting,numerical simulation joined saving production costs, improve productivity, andultimately achieve greater economic and social production core competitiveness ofproducts goals.Apparent viscosity model established in this paper, the research group ofsemi-solid Mg2Si/AM60composites based in VS2005fortran compiler softwareplatform with the apparent viscosity of semi-solid model of composite materials, andimport software FLOW-3D fluid simulation conducted secondary development.Apparent viscosity using the new model derived herein is based on magnesium alloydie-casting liquid filling the numerical simulation of the filling process and semi-solidfilling, respectively, to verify the new model can accurately describe the rheologicalsemi-solid filling capacity. And has been described by semi-solid castingconclusions filling the outer contour to get a clear, compact structure, fewer defectsforming castings. The use of FLOW-3D point tracking function, the key parts of thecover member were filling pressure and speed the process of tracking. The resultsshowed that when the semi-solid filling, pressure and velocity changes smoothly,evenly distributed, is conducive to forming high-quality castings. Die-casting and casting trials conducted microstructure were microscopic observation, the casting diecast microstructure resulting liquid coarse particles show its organization, organizedsemi-solid casting was finer, has once again proven describes a new model ofsemi-solid die-cast accuracy.In order to optimize the process parameters on the cover of semi-solid die-castparts were filling and solidification simulation, using orthogonal experiment methodof pouring temperature, speed punch, die preheating temperature of the processparameters were compared. The results showed that: mold filling time is very short,less than0.1S; impact punch speed and pouring temperature of filling to a large andpreheat temperature of the mold. The casting solidification analysis, the resultsshowed that: in the early stage of solidification, alloy liquid poured crossing nearmaintains a high temperature state to become part of the final solidification. In themain part of the cover member, because the semi-solid slurry solidification castingtemperature in the solid-liquid region, pouring temperature is lower than the liquidand semi-solid slurry itself, there is a high solid fraction, the semi-solid die-castingfast solidification. Start at a low temperature, pouring temperature of the bottom ofthe platform began, and then gradually spread to the Z-type thin-walled area, in linewith changes of the order of coagulation. From the end of the casting to complete thefilling with the solidification time is very short, the higher the temperature requiredfor the solidification of the casting time becomes longer, however, the preheatingtemperature of the mold and the solidification time of the punch speed is not affected.Analysis of the reasons may be the timing, the higher the mold preheat temperature,the lower the score the solidification curve. This shows that the high moldtemperature so that the solid solution alloy fraction decreased. Finally got the castingprocess parameters as temperature, speed punch, the mold preheat temperature,showed little defect distribution, excellent casting quality. Die-cast experimentsconducted using the optimal process parameters obtained, according to the results ofthe experimental program of optimum process parameters were validated.