【作者】 余胜胜；

【导师】 孙剑飞；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2011， 硕士

【摘要】 熔体抽拉非晶丝由于其独特的原子组态和几何尺寸,拥有良好的磁学和力学性能,在诸多领域具有广阔应用前景。熔体抽拉制备非晶丝过程中,润湿行为和熔潭特性决定了丝材成形能力,进而对后续丝材性能及其应用具有重要影响。因此研究熔体抽拉过程中成丝特性具有重要工程应用价值和意义。本文以Co_68.15Fe_4.25Si_12.25B_15.25合金为研究对象,耦合质量守恒、动量守恒、能量守恒方程,同时考虑熔体抽拉非晶丝成丝过程特定的工艺条件,结合流函数Ф的特性,建立了二维熔体抽拉润湿模型,并分析了不同热量传输控制因素和动量传输控制因素下熔体抽拉过程中的润湿行为。利用Fluent软件进行了熔体抽拉熔潭特性数值模拟,详细介绍了熔体抽拉辊轮参数和基本工艺参数对熔潭特性的影响规律,对模拟结果进行相应的理论分析,预测熔体抽拉缺陷形成并在此基础上与实验结果对比。不同轮盘材质下的动态抽拉润湿性:Cu轮<Mo轮<45#钢轮,这与相应基板下静态润湿性结果一致;轮盘材质不变情况下,仅改变辊轮表面与熔融母合金之间的初始静态润湿性,熔潭内部温度和速度无明显改变,熔体抽拉成丝特性基本保持不变;提高轮盘热导率,熔潭内部熔体剩余温度降低,润湿性变差,成丝特性降低。对于熔体抽拉工艺过程,提高轮盘转速,熔池长度和熔体抽拉层厚度减小,可以改善熔体抽拉过程成丝特性。轮盘转速较低时非晶丝表面容易形成瑞利波;轮盘转速过高时易于导致熔体抽拉层断裂而造成非晶丝长度减小。母合金进给速度对熔潭温度和速度分布影响较小;提高轮盘及母合金的初始温度,可以提高熔潭内部剩余温度,有效改善熔体抽拉成丝特性。更多还原

【Abstract】 As a result of the excellent magnetic and mechanical properties, melt extracted amorphous wires have been widely used for potential industrial application. During melt extraction process, the filamentization property is determined by the wetting and puddle properties, as a result to affect the property and application of amorphous wires. So it plays an important role in industry application to study on the filamentization property during melt extraction.This paper bases on the Mass Conservation Equation, Momentum Conservation Equation, Energy Conservation Equation and the specially process condition of melt extraction technique, which is combined with the characteristic of flow function, found the 2D wetting model during the melt extracting. The influence of different heat transmission and momentum transmission parameters on the wetting property is analyzed. The Fluent software is applied to simulate its puddle property. By altering concerned parameters, the influence of wheel and basic process parameters to puddle property is investigated in detail. The simulation results indicate that it can forecast the defects of melt extracted amorphous wires, and can be compared with the experiment data.The wettability of different wheel: copper wheel (less than molybdenum wheel) less than 45# steel wheel consists with static wetting result. The wettability remains as a constant if changing the static wettability between the wheel surface and molten alloy only, so do the temperature and velocity in the puddle. By enhancing the thermal conductivity of wheel, the temperature and the wettability will decrease. It can be obtained much better wettability with an increase of the wheel velocity, the decrease of the puddle length and thickness of the extracted layer. The amorphous wires will form Rayleigh waves defect on the surface when the wheel velocity is low. The molten layer becomes discontinuous with the high wheel velocity easily. The feed rate does not play a important role in the temperature and velocity distribution. The increasing temperatures of the puddle and the molten can effectively improve the wetting behavior during melt extraction process.更多还原