【作者】 龙欣江；

【导师】 程金树；

【作者基本信息】 武汉理工大学 ， 材料学， 2005， 硕士

【摘要】 近年来,国内外对建筑装饰微晶玻璃,即以β-硅灰石为主要晶相的微晶玻璃（CaO-Al₂O₃-SiO₂系统）研究报导很多,其中对硅灰石晶体的析晶过程、化学组成、生产工艺、产品性能研究较深入。随着CaO-Al₂O₃-SiO₂系统微晶玻璃产业的发展,在其工业生产中,存在难以解决的“变形”或“炸裂”等现象。这些问题的出现会大大降低产品的成品率,另外,也会给用户的使用带来不安全的因素。究其产生原因,是由于微晶玻璃中存在的玻璃相和晶相,他们在热膨胀系数、转变温度、力学性质、微观结构等方向有或大或小的差异,这些性质的差异必然导致残余应力的产生。有关微晶玻璃中残余应力等科学问题是非常值得研究的。但是,目前,国内外对于这个方面的研究深度不够。 由于金属材料良好的弹塑性、力学性能、机械加工性能,以及成熟的弹塑性力学的理论支持,所以在材料的内应力的研究方面,金属材料,金属薄膜,已经有了较深的研究,理论也比较完善。而无机非金属材料中的有关应力问题,有研究,但研究深度不够,理论也相对滞后。此外,如何控制并消除内应力,以最大限度降低内应力对材料的破坏。这些科学问题都值得在理论上加以深入研究。 因此,对于微晶玻璃的应力测试就尤显得重要。国内外在测试应力方面主要采用偏光仪、X射线应力测试仪、中子衍射应力仪、超声波应力测定仪等现代测试手段。根据本课题中所要研究的微晶玻璃的各方面性质,本文利用X射线应力测试仪及相关的软件实现了对其残余应力的测定。并且运用了其他现代测试手段,通过对微晶玻璃试样的结构及性能测定,全方面,多角度研究和分析了化学组成对CaO-Al₂O₃-SiO₂系统微晶玻璃中的残余应力的影响,探索相关基础理论问题,并将其与生产实践结合起来,指导同类材料的研究、开发与应用。 该测试方法利用X射线,以晶面间距作为应变的度量。当有应力时,晶面间距将发生变化,发生布拉格衍射时,产生的衍射峰也将发生移动,而且移动距离的大小与应力大小有关。根据弹性力学的公式可计算出残余应力的数值。本实验拟在RIGAKU公司生产的D/Max-ⅢA和D/Max-ⅢC型X射线衍射仪上进行。 实验结果表明:微晶玻璃的化学组成对其残余应力影响极其明显。随着CaO含量的增大,微晶玻璃中残余应力表现为先减小而后再急剧增大的趋势,而CaO含量为16wt%时,残余应力最小。当Al₂O₃含量从5.5wt%增加到9.5wt%,残余应力逐渐减小。在实际生产过程中可以能过合理地选择化学组成来减小微晶玻璃的残余应力,使其在一个可以允许的范围内,以满足正常生产及使用安全的要求。更多还原

【Abstract】 Recently, there are many researches on decorated glass-ceramics for building at home and abroad, and the main crystal phase of that is β-wollastonite. These researches cove crystallization, composition, technics, properties and so forth. With the development of CAS glass-ceramic industry, there are some intractable problems in the industry process, such as deformation and failure, which troubles the production, and leads higher cost and increases the danger in service. The residual stress in CAS glass-ceramics is the main reason for these phenomena. Unlike the normal glass, the CAS glass-ceramics, a heterogeneous composite material, consists of β -wollastonite crystal phase and glass phase. There are differences in some aspects between them, such as coefficient of thermal expansion, transition temperature, mechanical properties, microstructure, and so on, especially in the case of being heated, which inevitably induce residual stress in glass-ceramics. Though it is very valuable to study residual stress in glass-ceramics, the work in the field is not enough.Because of good elastoplasticity, mechanical properties and machinability in metal, and sophisticate elastopasticity theory, research on residual stress in metal or metal film has had a magnificent achievement. But, to the inorganic non-metal material, few reports about residual stress can be seen in the world, not to mention in-depth research. On the other hand, how to control and reduce the residual stress to minimize the breakage caused by residual stress is an important problem must be solved.So the role of measurement of residual stress is being highlighted. Now the typical means to measure residual stress are polariscope, X-ray diffraction, neutron diffraction, ultrasonic and so on. Considering the properties of CAS glass-ceramics, in this study, X-ray diffraction method on residual stresses measurement was used. Then modern testing means were used to test the properties and structure of CAS glass-ceramics, including XRD, FUR and SEM, which was useful for elucidating what influence the residual stress in CAS glass-ceramics. And the result of this research, combined with industry production, can help us to know the residual stress in other glass-ceramics and boost the invention of new glass-ceramics.In this study, we utilized the X radial incidence produced from cathode radial tube, and took the space between crystals as measurement of strain. When the stresses produced, the space between crystals changed and the diffraction peak moved during Bragg diffraction. The magnitude of movement is related to the stresses. Thus we can calculate the stress value. The test was carried out on the X-ray diffraction testinginstrument named D/Max-III A produced from RIGAKU Company of Japan.The results showed that increasing of the CaO content led to decrease initially, and then increase, and increasing of the Al2O3 content led to lower residual stress. So the optional content for CaO is from 16wt% to 18wt% and the optional content for Al2O3 is from 6wt% to 8wt%.Thanks for the financial support by National Science Foundation (50272043)!更多还原