【作者】 王栋；

【导师】 史铁林； 廖广兰；

【作者基本信息】 华中科技大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 非晶合金在常温下、微尺度时保持有极高的力学强度等性能,且在其过冷液态区具有优异的超塑性成形能力,因而被广泛认为是制备高强度微纳结构最具潜力的材料之一。本学位论文以Zr65Cu17.5Ni10Al7.5大块非晶合金为研究对象,针对其超塑性热压微成形工艺进行了研究,内容包括：(1)采用X射线衍射分析仪、差示扫描量热仪、力学性能试验机、热重分析仪等,系统研究了Zr65Cu17.5Ni10Al7.5大块非晶合金常温下的压缩断裂强度,过冷液态区温度范围以及在此温度范围内的等温氧化行为、等温晶化行为以及单轴压缩超塑性性能,为Zr基非晶合金的超塑性成形工艺的实施提供指导。(2)采用飞秒激光技术加工制备了微型齿轮金属模具,并应用于非晶合金的超塑性成形,成功制备了非晶态的微型零件。(3)在国内首次研究了基于硅模具的非晶合金复杂三维微型零件成形方法。采用体硅工艺批量制备出微型硅模具,应用于非晶合金的超塑性微成形,成功制备出非晶合金微零件。同时,采用DEFORM-3D有限元软件模拟分析了非晶合金在硅模具中的填充过程,对成形载荷和压头速度等参数进行了预测和优化,成功制备出模数为0.01mm、齿数为20的非晶合金微型直齿圆柱齿轮。(4)开展了利用硅模具进行一模多件制备非晶合金微型零件的工艺研究,包括微型硅模具的结构设计、侧壁参数优化、成形坯料尺寸形状选取等。实验研究了采用多层硅模具制备复杂三维非晶合金微型零件的工艺方案,制备出复杂的非晶合金微型多层齿轮。(5)自行设计了3K-1型微行星齿轮减速机构,对微型齿轮减速机构中的微零件成形方案进行了理论分析和实验研究,制备出了非晶态的微型行星齿轮减速机构各微型零件。非晶合金具有优异的性能,受到了人们的重视,基于其超塑性成形制备高性能的微型零件具有广泛的应用前景。当前,非晶合金的微成形技术研究正处于起步阶段,而基于其超塑性来成形制备复杂三维微纳结构／零件的研究有待于进一步加强。更多还原

【Abstract】 Bulk metallic glass was considered as one of the most potential materials because of the excellent super-plastic forming ability in the supercooled liquid region and mechanical properties in micron-size. In this paper, the superplastic hot embossing micro-forming technology of the bulk metallic glass was studied, which the composition elements ratio was Zr65Cu17.5Ni10Al7.5. Content as described below:The thermal stability of the samples, associating with the glass transition and crystallization, were examined by differential scanning calorimetric (DSC) to determine the temperature of supercooled liquid region, and the time-temperature-transformatiom (TTT) curve of the samples was obtained. Then, the compression strength at room temperature and the superplastic uniaxial compression performance at the supercooled liquid region have been tested by the Zwick Roell testing machine. The isothermal oxidation behavior has been researched by thermo-gravimetric analyzer (TGA). The studies provided the experimental basis for the papmeters option of the superplastic hot embossing micro-forming technology.The metal mold prepared by the femto-second laser processing technology was used to the superplastic hot embossing micro-forming technology of bulk metallic glass, and the armphous micro-part was prepared. Superplastic micro-forming of bulk metallic glass with silicon mold using hot embossing technology was studied, which was the firstly in china. The silicon mold prepared by the bulk silicon processing technology was used to forming the armphous micro-parts. The finite element simulation software DEFORM-3D was used to analysis the filling process in the silicon mold. The forming load was predicted, and the punch velocity was optimized. Finally, a good dimensional accuracy for a micro-spur gear with 0.1 module,20 teeth and a spline structure in the core was obtained by superplastic hot embossing forming technology.The process parameters of forming more than one at one time were studied, including the structural design of micro silicon mold, the thickness of silicon mold sidewall and the size and shape of blank. The forming process programs of complex multi-dimensional microstructure were designed using the multi-dimensional silicon mold. The complex amorphous multi-gear microstructure was prepared.3K-1 type micro planetary gear reducer was designed. The forming process programs of the micro-parts used in the micro planetary gear reducer were analyzed and testing studied. The armphous micro-parts were prepared.The study of bulk metallic glass was attentioned due to the excellent performance. The manufacture of the high performance micro-parts has broad application prospects basing on the superplastic forming techonology. The research on the micro-forming of bulk metallic glass was still in the initial stage. The preparetion of the complex three-dimensional micro-structure/parts basing on the superplastic micro-forming technology needs further study.更多还原