Study On Technology Of Preparing Aluminium Alloy Semi-solid Slurry By Gas-bubbling Method Combined With Mechanical Vibration

In comparison with casting and forging, semi-solid forming of metal has lowerprocessing temperature and deformation resistance. Therefore, semi-solid forming hasbecome one hot spot to research at home and abroad. However, it is limited to be usedbecause of the strict requirements of processing control, and that rises up the cost ofapplication. In this thesis, the economical composite method of gas-bubbling andmechanical vibration was used to research the production technique of ZL101semi-solidslurry and influence of structure and properties.We can use gas-bubbling method or mechanical vibration method or even both toprepare semi-solid slurry of light alloy with the equipment we designed which consists ofgas-bubbling agitation part, mechanical vibration part, lifting part, air-cooling part. Andthen all the experiments were operated on the equipment we designed.We systematic research on technology of preparing ZL101aluminium alloysemi-solid slurry by gas-bubbling method combined with mechanical vibration. Studiesshowed that the optimal parameters the preparation of semi-solid slurry by gas-bubblingmethod: agitate temperature is3℃to20℃below the liquid line, stirring3min, rotatedspeed is430r/min, gas flow rate is2L/min, holding time is3min. The optimal parametersthe preparation of semi-solid slurry by mechanical vibration: optimal vibration time is5min, the amplitude and frequency are the bigger the better with the permittingconditiongs. Optimal composite process as follows: apply mechanical vibration at thebeginning of air stirring, agitate3min，stirring3~5min. With the0ptimal compositeprocess we get ZL101aluminium alloy semi-solid slurry, the mean roundess is0.42, theequivalent diameter is60.92μm, the tensile strength is170.9Mpa, the extension rate is5.43%.In addition, the mechanism of semi-solid slurrying by mechanical vibration methodwas researched. with mechanical vibration,large amount of dendritic microstructure for thereason of melt supercooling and grains grew uniformly at each direction because of thegrain movement caused by vibrat convection are the main reasons of formation ofnon-dendritic microstructure of semi-solid alloy.