流变铸造Al-20Si合金  

Rheocasting of Hypereutectic Al-20Si Alloy

作　　者：郭洪民[1] 杨湘杰[2] 胡勇克[3] 

机构地区：[1]南昌大学材料科学与工程学院 [2]南昌大学机电工程学院 [3]南昌大学资产处

出　　处：《特种铸造及有色合金》2007年第11期843-846,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(50474007);江西省自然科学基金资助项目(0450050);江西省教育厅科技项目

摘　　要：研究了剪切低温浇注式半固态浆料制备工艺(LSPSF)对Al-20Si过共晶合金中初生Si相尺寸和形貌的影响。结果表明,LSPSF工艺可制备质量优良的Al-20Si合金半固态浆料和坯料;初生Si得到明显细化,分布均匀,形态发生了明显改变,由板片状转变为多角块状;磷变质处理可强化LSPSF工艺的细化效果,但浇注温度过低时,初生Si相发生偏聚。在LSPSF工艺条件下,初生Si得以细化和圆整化主要归因于LSPSF工艺引起的增强异质形核作用和抑制初生Si择优生长作用。Effects of low superheat pouring with a shearing field(LSPSF) on the grain size and morphology of primary Si in hypereutectic Al-20Si alloy have been observed.The results show that semi-solid Al-20Si alloy slurry and billets with excellent quality can be prepared by LSPSF.Primary Si with uniform distribution is converted from plate-like structure into polygonal bulk structure,obtaining obvious refinement.The LSPSF refining effects can be enhanced by P modification,however,the segregation of primary Si phase can be observed with lower pouring temperature.The refinement and spheroidization of primary Si in the Al-20Si alloy is attributed to enhancing heterogeneous nucleation and controlling the anisotropic growth of primary Si phase by LSPSF.

关 键 词：流变铸造 过共晶铝硅合金 AL-20SI 微观组织 凝固 

分 类 号：TG27[金属学及工艺—铸造]