半固态铝合金浆料的复合制备和流变成形研究  

Composite Slurry Preparation and Rheocasting of Aluminum Alloy

作　　者：毛卫民[1] 汤国兴[1] 白月龙[1] 赵振铎[1] 

机构地区：[1]北京科技大学材料科学与工程学院

出　　处：《特种铸造及有色合金》2007年第7期493-495,共3页Special Casting & Nonferrous Alloys

基　　金：国家高技术发展计划(863计划)资助项目(2006AA03Z115);国家重点基础研究发展计划(973计划)资助项目(2006CB605203);国家自然科学基金资助项目(50374012)

摘　　要：利用短时弱电磁搅拌和低过热度浇注制备了半固态AlSi7Mg铝合金浆料,随后对该浆料进行了均热处理,并探讨了浆料温度、压射比压与压射速度对铝合金浆料流变成形过程的影响.制备结果表明,在630～650 ℃下浇注,同时辅以短时低强度电磁搅拌,AlSi7Mg合金中的初生α-Al呈现为球状,个别的初生α-Al呈现为蔷薇状;在固液两相区进行均热处理时,促进了初生α-Al的熟化作用,使初生α-Al进一步球化和粗化.成形结果还表明,浆料温度、压射比压和压射速度对半固态AlSi7Mg合金浆料的充填性影响较大,压射比压和压射速度越大及浆料温度越高,型腔越容易充满;铁芯位置距离内浇道越近,越有利于半固态AlSi7Mg合金浆料的充填;对于试验的钥匙铸件,只要浆料温度≥585 ℃,或压射比压≥20 MPa,或压射速度≥1.73 m/s,半固态AlSi7Mg合金浆料都可充满型腔.流变成形铸件的组织分布很均匀,表明采用低过热度浇注和弱电磁搅拌相结合所制备的半固态AlSi7Mg铝合金浆料适合流变成形,有利于获得高质量的压铸件.The semi-solid slurry of AlSi7Mg alloy was prepared by being poured at a low superheat and stirred at a low power electromagnetic field for a short time,and then the slurry was further soaked for proper time and finally rehoformed into a key-shaped die cavity.The influences of slurry temperature,injection specific pressure and injection rate on the rheoforming process were investigated.The results show that the major spherical primary α-Al phase and a little rosette-like primary phase in the AlSi7Mg alloy can be observed with pouring at 630～650 ℃ and stirring by an a low power electromagnetic field for a short time.The primary α-Al phase can be further spheroidized and coarsened as a result of accelerate ripening of primary α-Al phase by soaking treatment at liquid-solid zone for some time.The experimental results reveal that the slurry temperature,injection specific pressure and injection rate have great effects on the filling ability of semi-solid AlSi7Mg slurry,where the higher the slurry temperature,injection specific pressure and injection rate are,the higher the slurry filling ability and the shorter the core distance for the ingate are and the easier the filling of semi-solid AlSi7Mg alloy is.The slurry can fully fill the cavity of key parts with the slurry temperature more than 585 ℃,or the injection specific pressure more than 20 MPa,or the injection rate more than 1.73 m/s.The key parts have uniformly distributed microstructures,showing that the above-mentioned methods can be suitable for producing the semi-solid parts with high quality.

关 键 词：半固态 电磁搅拌 流变成形 显微组织 ALSI7MG合金 

分 类 号：TG244[金属学及工艺—铸造]