Effect Of Power Ultrasonic On Semi-solid Structure Of Flowing A356 Melt

A356,with good forming property in semi-solid state,is the widely used alloys incommercia l production of semi-solid processing technology. Preparation of semi-solidslurry is the key of semi-solid forming technology, and preparation semi-solid slurrywith power ultrasonic is a considered environmental material forming process in the21st century. Depth and extensive study of the power ultrasonic on basic theory of grainrefinement and application of technology was done by many domestic and foreignresearchers, that a certain amount of static alloy melt was dealt with power ultras onic.But most of researches have been limited in the laboratory and can not meet the needs ofindustrial production. Based on the industrial needs and results of our research project,semi-solid slurry was prepared by power ultraso nic on flowing A356 melt, to breakthrough the limitations on use .On preparation of semi-solid aluminum alloy slurry with power ultrasound , mostresearchers considered a certain amount of static alloy melt as research object, andprocess factors that included the strength of power ultraso nic and treatment temperaturewere selected. In this paper, based on previous study of our research group, who haddone a more in-depth study, a new kind of power ultrasonic device and experimentalprogram were adopted, to prepare A356 semi-solid slurry. Three mair process factorsthat included the strength of power ultrasonic , treatment temperature and the dista nce ofdisposal area (from tool head to the bottom of melt channel) were selected in thisexperiment, then different process parameters were used to design experimentalprogram, design of the orthogonal was optimized by interaction of the strength of powerultraso nic and treatment temperature, According to experimental results, the optimalcombinations of the parametes were determind .To study the influence of cooling rate onsemi-solid slurry organization, the effect of structure under different cooling methods ofair cooling and water cooling was analyzed. Finally, the best microstructure of A356alloy obtained by this experiment and the pre-experiment (power ultrasonic on staticA356 alloy melt)was compared.According to the results, the range of loading power from 800W to 1000W, withthe strength of power ultrasonic increasing, effect of A356 alloy refining was moreobvious , when the strength of power ultraso nic is up to 1500W,the effect of structurewas worse; And that the best prima ry phase was obtained at the 615℃among the four treatment temperature (645℃, 630℃, 615℃, 600℃); with the increase of thedistance of disposal area , among four groups data (7mm, 9mm, 12mm, 15mm) , thestructure of A356 alloy was more coarse and the segregation was more serious .The bestprimary phase obtained power ultraso nic on a certain amount of meltα- Al wasD=30.5um, f=0.81 ,and the best prima ry phaseα- Al was D=22.56um, f=0.78 in thisstudy.In short, preparation of semi-solid slurry with power ultraso nic on flowing A356melt is a new approach. It broke through the traditiona l concepts , optimizedma nufacturing processes and met the needs of industria liza tion.