| The balance of resources and environment has put forward higher requirements for modern industry,Some traditional iron and steel products are gradually replaced by new light alloys,so that aluminum and aluminum alloys are widely used in many transportation industries such as high-speed trains,aerospace and so on,the lightweight of traffic can not only carry out technical reform in structure,but also can be used as a choice in lightweight materials.The emergence of semi-solid metal processing technology,which is known as one of the most promising metal forming processes in the 21 st century,has made many researches in the country because of its high processing efficiency,short process and good performance of processed parts.The research on semi-solid processing technology has further promoted the development of light alloy industry.The method of preparing semi-solid aluminum alloy slurry by consumable stirring method used in this paper refers to stirring the metal solution with A356 rod of the same composition and rod refiner,so that the stirring rod is gradually melted in the metal mother liquid.The stirring methods are mechanical stirring and ultrasonic-assisted stirring,respectively.A356 alloy with wide solid-liquidus line and excellent performance was selected,and the process parameters were analyzed through experiments,and the high-quality semi-solid aluminum alloy slurry for transportation field was prepared by self-consumption stirring method.The influence of process parameters of consumable stirring method on the quality of semi-solid slurry was studied by microscopic observation,electronic scanning observation,phase analysis and mechanical property test.The main conclusions of this paper are as follows:(1)In the self-consumption stirring process,by controlling the material of the stirring rod,the insertion temperature of the stirring rod and the pulping time,the pulping quality can be significantly improved,and the prepared semi-solid slurry has spherical or nearly spherical crystals,which are evenly distributed in the in the melt.(2)Compared with ultrasonic vibration,mechanical stirring can make the slurry structure more fine and regular.The refining effect of semi-solid slurry prepared by refiner stirring rod is more significant than that prepared by A356 stirring rod.It can not only change the size of slurry structure,but also change the coarse needle and flake Si phase in the slurry into fine point and short rod shape,so that the quality of semi-solid slurry can be significantly improved.(3)When the stirring temperature was 615℃ and the stirring time was 60 s,the A356 aluminum alloy semi-solid slurry was mechanically stirred with an A356 stirring rod after adding 0.4% refiner.The quality of the prepared A356 aluminum alloy semi-solid slurry reached the highest,and the grain size was 62.53μm.The grain size is 64.3% higher than that of A356 alloy without external conditions.The mechanical properties of A356 alloy are also improved the most,the tensile strength is increased from 162.9Mpa to 213.35 Mpa,the elongation is increased from 4% to 12.4%,and the tensile fracture exists in the form of dimple.(4)The technology of preparing semi-solid aluminum alloy slurry by consumable stirring method has the advantages of practicality,high efficiency,simplicity and easy popularization. |
