Study Of TiAl-based Multi-component Alloy By Vacuum Induction Electromagnetic Levitation Refining

TiAl-based alloy,which has some excellent performances,such as low density,high specific strength,high specific rigidity,oxidation resistance,creep resistance and etc.,has great potential in manufacturing heat-resistant structural parts of engines for aerospace,aviation and automotive.Therefore,the development of TiAl alloy has been the concern and attention of researchers all over the world.In this paper,TiAl-based alloy was prepared by aluminum thermal reduction method and vacuum refining with Panzhihua acid-soluble titanium slag as raw material.And then,the chemical composition,microstructure,phase structure and mechanical properties of the TiAl-based alloy were characterized and tested by Chemical Analysis,EDS,SEM,XRD and Universal Material Experiment Machine.In addition,the saturated vapor pressure of each element of TiAl-based alloy was calculated by the saturated vapor pressure equation.And we also used Pandat to calculate and draw phase diagrams.We mainly get the following achievements by studying the effects of refining heating power,refining atmosphere,refining times and refining times on the chemical composition,microstructure and mechanical properties of TiAl-based alloy.Three diagrams of vertical cross-section which is rich in titanium were drawn by Pandat,and the three diagrams are related to Ti-34Al-9Fe-4Si-xMn?x<2?,Ti-34Al-9Fe-ySi-1Mn?y<6?,Ti-34Al-zFe-4Si-1Mn?z<12?.The results showed that the addition of Mn element mainly forms the Al8Mn5 phase at room temperature equilibrium,and with the increase of Mn content,each phase of the phase diagram moves to the left;the addition of Si element mainly forms the Ti5Si3 phase at room temperature equilibrium,and with the increase of Si content,alloy liquidus rise and all phase areas move to the left side of the phase diagram;the addition of Fe element mainly forms the H_L21 phase?solid solution phase?at room temperature equilibrium,and with the increase of Fe content,alloy liquidus rise slightly and all phase areas alse move to the left side of the phase diagram.The saturated vapor pressure was calculated by vapor pressure equation of alloy element.The results showed that the saturated vapor pressure of each element in the alloy is as P_Mn>P_Al>P_Fe>P_Si>P_Ti.The TiAl-based alloy prepared by aluminum thermal reduction method?the coarse alloy?contains more impurities,oxygen content of 1.4%,microstructure sparse,vickers hardness of 518.77 MPa.Vacuum induction magnetic levitation refining can effectively remove the slag in the coarse alloy,reduce the content of impurities and reduce the oxygen content,the microstructure of the alloy is more compact.