【作者】 刘旭波；

【导师】 杨湘杰；

【作者基本信息】 南昌大学 ， 材料加工工程， 2007， 博士

【摘要】 本文研制了新型的剪切低温浇注式(LSPSF-Low Superheat Pouring with aShear Field)半固态浆料制备工艺试验装置；研究了该装置制备铝合金半固态浆料的工艺；分析了材料智能处理技术(IPM-Intelligent Processing of Materials)在半固态技术领域的应用和发展方向，根据该分析，构建了基于PC平台的温度模糊控制系统；研究了半固态金属电导率和其微观组织的关系。论文主要工作和结论如下：1、首先研制了该装置的基于单片机和PID控制技术的温度控制系统，该系统由于其较高的控制精度(±1°C)和操作的简易性，为LSPSF工艺的实验研究可靠性和稳定性提供了保障。2、应用LSPSF工艺装置和所建立的控制系统，研究了铝合金半固态浆料的LSPSF法在线制备工艺，通过对ZL101、ZL201和A380铝合金浆料制备的工艺研究，得出如下结论：应用LSPSF法进行铝合金半固态浆料制备，只有浇注温度与输送管速度达到很好地匹配时，才能有效地提高有效形核数目，进而获得理想的半固态浆料。在本实验装置的技术参数条件下，获得优良细小近球形晶组织的工艺条件：(a)输送管转速100±10r／min；(b)浇注温度：液相线以上30±10℃；(c)输送管倾角20度时，浆料蓄积器温度500±50℃。3、介绍了材料智能处理的概念、原理和关键技术。结合半固态金属成形技术的特点，提出了材料智能处理在半固态成形工艺过程的应用可从仿真预测技术和工艺过程智能控制技术方面开展工作。主要观点如下：(a)材料智能处理在金属半固态成形技术应用的重点是新型传感器的研制以及现代控制技术的应用。(b)为满足半固态成形工艺检测和控制的技术特点，新型的传感器应该能够反映浆料的微观组织性能，并且能够实现材料性能的非接触式在线检测。(c)为使金属半固态成形技术获得实际生产的应用，在控制技术上不但要加强新型智能控制技术理论的应用，而且为了促进半固态成形工艺与其他工艺环节的融合，根据现代控制技术的潮流，在硬件上还应该开发基于PC平台的控制系统，充分利用PC软硬件技术的丰富资源和强大功能。4、针对以上观点，研制了基于PC平台、应用了智能模糊控制技术的温度控制系统。该系统以PC机为硬件平台，应用组态王作为开发软件，在控制上应用模糊控制技术作为信息的处理和控制。经过计算机仿真和实验应用验证，证明通过模糊智能控制技术的应用，所建立的温度控制系统超调小、精度高、动态响应较快和鲁棒性好，克服了以前所建立的基于单片机和PID控制技术温控系统温度过冲大、动荡时间较长等缺点。5、研究了半固态成形ZL101铝合金和A380铝合金试样在室温下电导率和其微观组织结构的关系。针对金属半固态成形的特点，考察了半固态成形铝合金微观组织中的初生固相率、晶粒等效直径和晶粒形状因子三个因素各自对电导率的影响。结论如下：(a)铝合金电导率随着其初生固相率的增加而增加；(b)铝合金电导率随着其微观晶粒等效直径的增加而增加；(c)铝合金电导率随着其晶粒形状因子的增加也呈增加趋势；以Sn-15wt.％Pb合金为对象，研究了其在半固态温度区间，不同等温温度对其微观组织的演变影响以及因此而造成的对其电导率的影响。结论如下：(a)在半固态温度区间范围内，等温时间一定，随着等温温度的提高，其固相率降低，其导电率随之降低。(b)在一定等温温度下，半固态Sn-15wt.％Pb合金的导电率可以表示为等温时间的单调递增函数。因此在其半固态浆料制备工艺中可以配合温度控制，合理地控制其电导率，进而控制其微观组织结构。更多还原

【Abstract】 A device and it’s controlling system for a new efficient rheocasting process, termed Low Superheat Pouring with a Shear Field(LSPSF), is developed. The effects of LSPSF parameters on the microstructure of aluminum alloys semi-solid slurry were studied. The application and developing trend of IPM (Intelligent Processing of Materials) in the technology of semi-solid process is intruduced. Accord to the concept of IPM, a temperature controlling system based on Fuzzy control and PC controlling technology was developed. The relation between electrical conductivity and microstructure of semi-solid alloys was investigated. The main work and results presented as follows:(1) In order to improve the precision and stability of LSPSF process, a temperature controlling system based Single Chip Micyoco and PID technology was developed. The higher precision(around±1℃) and facility of the system are important and efficient to the LSPSF process.(2) A series of experiment using aluminum alloys of ZL101, ZL201, A380 were carried out to studied the effects of the LSPSF parameters on the microstructure of aluminum semi-solid slurry. The results are as follows:Under the condition which only when the pouring temperature and the rotation speed of duct matching well, it can be carried out that the LSPSF process has high efficiency of duct making with high quality of microstructure. It’s concluded that the choiceness condition of LSPSF process is:(a) The rotation speed of duct is around 100±10r/min;(b) The pouring temperature is around 30±10℃above liquidus temperature;(c) The temperature of slurry container is around 500±50℃.(3) The conception, principle and key technology of IPM (Intelligent Processing of Materials) are introduced. Considering the specialty of semi-solid process, a viewpoint is brought forward in the paper that the application of IPM on semi-solid technology should start with two directions: technology of simulation and forecast, technology of process intelligent controlling. The main viewpoint presented as follow:(a) The keystone of the application of IPM on semi-solid process is new sensor researching and modern controlling technology applying.(b) According to the speciality of semi-solid technology, the sensor can reflect the performance of microstructure of slurry with non-contact checking on the manufacturing line.(c) The controlling system based on the PC control should be developed for semi-solid process, which applying the modem intelligent controlling theory.(4) According to the viewpoint above, a intelligent temperature controlling system using fuzzy control theory based on PC is developed. Using kingview6.5, the system software is designed. Through the simulation and the experiment, the result shows that the new temperature controlling system have high quality of temperature controlling. The precision(around±1℃) and stability are all better than the system based PID controlling.(5) The relation between electrical conductivity and microstructure of ZL101 alloy and A380 alloy is studied. The important parameters of microstructure which affect the electrical conductivity is the solid phase ratio, equivalent diameter, shape factor. A conclusion is brought out as:(a) The electrical conductivity of aluminum show itself a trend of increasing along with the solid phase ratio increasing.(b) The electrical conductivity of aluminum show itself a trend of increasing along with the equivalent diameter increasing.(c) The electrical conductivity of aluminum show itself a trend of increasing along with the shape factor increasing.Using the Sn-15wt.% Pb alloy, the affect on the electrical conductivity of different temperature between the semi-solid temperature range, and different time of isothermal heat-treatment is studied. The conclusion presented as follow:(a) When the isothermal time keeps invariable, the electrical conductivity of Sn-15wt.% Pb alloy show itself a decreasing trend along with the isothermal temperature increasing between the semi-solid temperature range.(b) When the isothermal temperature keeps invariable, the electrical conductivity of Sn-15wt.% Pb alloy show itself a increasing trend along with the isothermal time increasing.According to this conclusion, the electrical conductivity can be used to control the quality of microstructure of semi-solid slurry.更多还原