本文選題：晶粒細(xì)化 + 脈沖電磁場　； 參考：《工程科學(xué)學(xué)報》2017年12期

【摘要】：采用一種新型熔體表面脈沖電磁技術(shù)對7A04鋁合金半連續(xù)鑄造凝固組織細(xì)化處理,分析脈沖電磁場對凝固組織及性能的影響.引入勢能的觀點(diǎn),探討脈沖磁能作用下的晶體形核動力學(xué)及初生晶核運(yùn)動形式.結(jié)果表明,經(jīng)表面脈沖電磁場處理后,凝固組織由晶粒尺寸粗大的玫瑰結(jié)構(gòu)轉(zhuǎn)變?yōu)榧?xì)小且圓整的球狀結(jié)構(gòu),鑄錠心部及邊部晶粒尺寸分別下降22.7%和14.2%,強(qiáng)度、塑性均有提高.動力學(xué)分析認(rèn)為,脈沖電磁能降低體系形核所需的臨界吉布斯自由能是增加形核率的重要原因,同時可導(dǎo)致初生α-Al運(yùn)動的勢能增加,促使初生α-Al顆粒優(yōu)先到達(dá)穩(wěn)定位置.
[Abstract]:A new melt surface pulsed electromagnetic technique was used to refine the solidified microstructure of 7A04 aluminum alloy in semicontinuous casting. The effect of pulsed electromagnetic field on solidification microstructure and properties was analyzed. From the point of view of potential energy, the crystal nuclear power theory and the motion form of primary crystal nucleus under the action of pulsed magnetic energy are discussed. The results show that the solidification microstructure changes from the rose structure with coarse grain size to the fine and round spherical structure after the treatment of surface pulsed electromagnetic field. The grain size in the center and edge of the ingot decreases by 22. 7% and 14. 2% respectively. The strength and plasticity of the solidified structure are improved. The kinetic analysis shows that the reduction of the critical Gibbs free energy required for nucleation is an important reason for increasing the nucleation rate. At the same time, the potential energy of the primary 偽 -Al motion increases, and the primary 偽 -Al particle preferentially reaches the stable position.
【作者單位】： 內(nèi)蒙古科技大學(xué)材料與冶金學(xué)院;
【基金】：國家自然科學(xué)基金資助項目(51044002) 科技部國際合作資助項目(2010DFB70630)
【分類號】：TG292

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本文編號：1932399