Effect Of Semi-solid Formation Technology On The Structure And Mechanical Property Of Al-5Fe Alloy

The paper aims at the problems of thick fragility needle-like or needle-plate like iron-richphase of AI-Fe alloy severity rend the basal body and deteriorate mechanical property of thealloy; We develop the research work of improving the microstructure and the mechanicalproperty of the alloy. The structure has been refined by semi-solid forming technology. Theinfluence of the electromagnetic stirring, nearby liquidus, reheat, different extrusion ratio andheat treating process to the structure and performance of the alloy has been studied.The experimental results indicate that electromagnetic stirring can effective improveAl₃Fe phase of the alloy, changing it from extremely thick needle-plate like to thinshort-needle like, when increasing the stirring voltage, the refinement effect will be better. Inthe experiment, when the electromagnetic stirring voltage is 100v, the length of needle-likephase decreases 75% comparing with as cast condition; the nearby liquidus also can effectiverefine the structure of the alloy, the Al₃Fe phase obvious refined, the thickness obviousdecreased, and partial Al₃Fe phase transition into graininess at 775℃. As the soaking timegrows, the primary iron phase changes from thick to refining, then grow up once again. In thispaper, the soaking time is 30min.Reheat make local Al₃Fe phase dissolve, the sharp comer vanish and thickness reduce.The higher the reheat temperature, the more obvious the phenomenon of dissolve. In thispaper, the reheat temperature is 680℃and soaking time is 30min.Semi-solid Formation could further refine Al₃Fe phase of Al-5Fe alloy. The higher theextrusion ratio, the more obvious the effectiveness of refining and breaking. In the paper, theSemi-solid stock is made by both electromagnetic stirring and nearby liquidus. Whenextruding the stock made by electromagnetic stirring, the length of Al₃Fe phase is about 30μm,decreasing 85% comparing with as cast condition. When extruding the stock made by nearbyliquidus, the length of Al₃Fe phase is about 20μm, decreasing 90% comparing with as cast condition. The heatment can improvement the structure of alloy, the proper processing is480℃×2h solution treatment, water quench.Semi-solid Formation can improve the mechanical property of Al-Fe, and comparingwith the increasing extrusion ratio, the tensile strength and elongation percentage is improved.The maximum tensile strength is 146.SMPa, increased 37% comparing with as cast condition,the elongation percentage could reach 27.4%.