【作者】 李桂荣； 王宏明； 赵玉涛； 程晓农； 陈刚；

【Author】 LI Gui-rong, WANG Hong-ming, ZHAO Yu-tao, CHENG Xiao-nong,CHEN Gang (Institute of Materials Science and Technology,Jiangsu University, Zhenjiang 212013,China)

【机构】 江苏大学材料科学与工程学院；

【摘要】 为满足汽车轻量化、高强度对新材料的要求,在实验室条件下制备了Mg2Si颗粒增强铝基原位复合材料。选用纯铝、结晶硅、Al-50%(质量分数,以下同)Mg中间合金配制过共晶AlMgSi熔体,在无搅拌、电磁搅拌两种条件下在石墨模具中铸态成型。设定电磁搅拌器中心部位磁感应强度为0.015和0.03T。Mg2Si相在凝固过程中原位析出为铝基体的颗粒强化相,其理论质量分数为20%。金相和SEM检测结果显示,无搅拌试样中初晶Mg2Si尺寸为20～40μm,呈块状,在基体中分布弥散均匀;共晶Mg2Si呈枝杈状;搅拌试样中块状初晶Mg2Si尺寸增大,并呈明显的"中心少、边缘多"的偏析,具有梯度效应和表面强化的效果,共晶Mg2Si呈手指纹状。0.03T时搅拌铸造试样中颗粒分布的梯度效应较0.015T的明显。分析认为,无论是初晶还是共晶Mg2Si相都会受到冷却凝固条件的影响。在过共晶Al-Mg-Si合金熔体凝固过程中施加适当的电磁搅拌有利于制备Mg2Si颗粒增强梯度铝基复合材料。更多还原

【Abstract】 In order to meet the demands of light weight and high strength in automobile industry, in situ Mg2Si particle reinforced aluminum matrix composites were prepared.Pure aluminum, crystallized silicon and Al-50wt% Mg interalloy are utilized to synthesize hypereutectic AlMgSi melt. The melt is cast in graphite mold without and with electromagnetic stirring (EMS).The The electromagnetic induced intensity at center of electromagnetic stirring apparatus are set as 0.015 and 0.03T. The corresponding magnetic induced intensity is The Mg2Si particle in situ crystallized during solidification .So the Mg2Si particles reinforced aluminum matrix composites were in situ fabricated with 20wt% weight fraction. The metallographic and SEM analysis result show that in the sample without EMS the morphology of primary Mg2Si is like block ,the size of which is the range of 20-40μm. The particles well distribute in the matrix. While pattern of eutectic Mg2Si is like branch. However, the size of primary Mg2Si in the sample with EMS increases. The amount at edge is larger than that in the inner part ,which exhibits the character of surface reinforcing. And the eutectic Mg2Si shows like dectylogram. The gradient effects of particulate distribution in the samples fabricated with 0.03T EMS are more apparent than those with 0.015T.So it can be concluded that both the primary and eutectic Mg2Si would be influenced by the solidification condition. Selected casting method without stirring the uniform Al-Mg2Si composites can be got while selected casting with EMS the Al-Mg2Si gradient reinforced composites can be got.更多还原