电磁搅拌铝合金热模浇注温度对其凝固行为的影响  

Effects of Pouring Temperature on Solidification Behavior of Aluminum Alloy Melt with Electromagnetic Stirring

作　　者：王晶[1] 何良菊[1] 李培杰[1] 

机构地区：[1]清华大学机械工程系

出　　处：《特种铸造及有色合金》2009年第4期334-336,共3页Special Casting & Nonferrous Alloys

摘　　要：将电磁搅拌后不同过热温度的A356铝合金熔体浇注到约550℃的高温铸型中制备半固态浆料。利用光学显微镜和Image-ProPlus图像分析软件对获得的浆料组织进行分析,研究了A356合金过热熔体在浇注过程中的凝固行为。结果表明,过热温度为710℃的合金熔体在随后的浇注过程中形核率小,浆料中α-Al初晶仍为发达的树枝晶组织。过热温度为670℃时合金熔体浇注时有效形核率开始大幅增加,初晶在数量和形状上逐渐由树枝晶趋向于非枝晶。过热温度为630℃的合金熔体经浇注获得的浆料组织中,平均圆整度为1.35的非枝晶在初晶中所占的比率达到约60%,晶粒平均尺寸约为30μm。Semi-solid slurry was prepared by pouring A356 superheated melt with different temperature with electromagnetic stirring into a hot mold at 550℃. Microstructure of the prepared slurry was observed by OM ( optical microscope) and Image-Pro Plus software to understand the solidification behavior of aluminum alloy A356 superheated melt during pouring process. The results indicate that primary α-Al phase exhibits developed dendritic structure in the slurry with pouring at 710 ℃ as a result of low nucleation rate. Primary phase is converted gradually from dendrite into non-dendrite with pouring at 670 ℃ due to the great increase of effective nucleation rate in the melt. Microstructure with about 60% non-dendrite in the primary phase can be obtained with pouring at 630 ℃, in which non-dendrite with about 30 μm in size and 1.35 in roundness can be observed.

关 键 词：热模浇注 电磁搅拌 A356合金 半固态 

分 类 号：TG249.9[金属学及工艺—铸造]