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以6061合金为研究对象,采用降低浇铸温度同时施加电磁场的半连续铸造工艺,研究了ZL201合金的凝固组织,并进行了二次加热实验。结果表明:在液相线温度附近施加电磁场,合金组织为均匀、细小非枝晶组织;低过热度浇铸时,临界晶核半径减小,此时在电磁场作用下,降低了熔体的温度梯度,促进了准固相原子团簇在熔体中形成,形核率增大;二次加热时,随着保温温度的升高,组织转变速度加快,保温温度过高,淬火组织粗大,对成形件性能不利;随着保温时间的增加,初生α-Al不断球化,淬火组织也越圆整;在610～630℃下保温15min,所得淬火组织均匀,细小,是理想的重熔组织。
Taking the 6061 alloy as the research object, the solidification microstructure of ZL201 alloy was investigated by using the semi-continuous casting process with the decrease of casting temperature and the application of electromagnetic field. The secondary heating experiment was also conducted. The results show that when the electromagnetic field is applied near the liquidus temperature, the microstructure of the alloy is uniform and small non-dendritic structure. When the superheat degree is cast, the radius of the critical nucleus decreases. Under the action of electromagnetic field, the temperature gradient of the melt decreases , Promoted quasi-solid atomic clusters formed in the melt, the nucleation rate increased; secondary heating, with the holding temperature, the organization to speed up the transformation, the holding temperature is too high, hardened tissue coarse, the shape of Performance is unfavorable. With the increase of holding time, the primary α-Al is continuously spheroidized, and the harder the structure is also more round. At 610-630 ° C. for 15 min, the obtained quenched structure is uniform and small, which is an ideal remelting structure.