Microstructure And Mechanical Properties Of High-entropic Alloys Prepared By Additive Manufacturing Technology

HEAs,as a new multi master alloy material,has attracted much attention in the field of metal materials because of its unique solid solution structure and excellent comprehensive properties such as high hardness and high strength.Due to the rapid forming characteristics of"quench and heat",the material-increasing manufacturing technology has become one of the most promising manufacturing methods in the preparation of complex metal components.The preparation of high-entropic alloy parts based on the material-increasing manufacturing technology will inevitably become one of the hottest research topics with broad application prospects.In this paper,different kinds of high-entropic alloys are prepared based on material-increasing manufacturing technology.The influence laws of different laser process parameters on forming quality of high-entropic alloys are studied by combining simulation with experiment.Through establishing simulation model of temperature field of laser cladding melting pool,the law of temperature change of during laser cladding is analyzed and the theoretical research combined.The factors influencing the micro-structure,macro-forming quality and mechanical properties of high-entropic alloys are analyzed,and the factors influencing the grinding properties of different high-entropic alloys are analyzed through the experiment of manufacturing high-entropic alloys by adding materials.The main contents include the following points:(1)To explore the thermodynamic basis and forming theory of high-entropic alloy,to study the thermal interaction between laser and multi-element metal powders,the matrix and the flow control theory of molten pool,and to analyze the causes of formation of surface tension of molten pool and the solidification theory.Combining with theoretical analysis,the variation rule of temperature field in molten pool during simulation of laser cladding process with different process parameters is explored as well as the temperature gradient along different directions,and the variation rule of temperature in molten pool with time is explored in this study.(2)To discuss the influence rule of laser process parameters on the size of high-entropic alloy cladding layer prepared by laser melting deposition,to analyze the morphology and characteristics of micro-structure of high-entropic alloy cladding layer,to explore the influence rule of different content of added elements on the forming quality of high-entropic alloy cladding layer,and to verify the accuracy of simulation model by comparing simulation and experiment of laser melting deposition high-Entropy alloy.(3)The influence laws of different particle size,element content and process parameters on macro-forming quality,micro-structure morphology and mechanical properties of selected laser sintering high-entropic alloy specimens were analyzed,and the crystal phase composition and distribution rules in high-entropic alloy specimens were discussed as well as the influence laws of different height of specimens on tensile properties of specimens.(4)The influence of processing parameters and Al element content on the processing performance of high-entropic alloy in as-cast high-entropic alloy was investigated,and the processing performance in as-added material manufacturing was also compared and analyzed.