| Recently, there have been many researches on architectural decoratedglass-ceramic at home and abroad, and the main crystalline phase of that isβ-wollastonite. With the development of CAS glass-ceramic industry, there are someintractable problems in the industry process, such as transmogrification or burst. Theemergence of these problems can deeply reduce the rate of finished products, thusaffect the economic benefit of enterprises and the development of industrial technique.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 ofβ-wollastonite crystal phase and glass phase. There are differences insome aspects between them, such as coefficient of thermal expansion, transitiontemperature, mechanical properties, microstructure, and so on, especially in the caseof being heated, which inevitably induce residual stress in glass-ceramics. Though itis very valuable to study residual stress in glass-ceramics, the work in the field is notenough.Because of good elastoplasticity, mechanical properties and machinability inmetal, and sophisticate elastopasticity theory, research on residual stress in metal ormetal film has had a magnificent achievement. But, to the inorganic non-metalmaterial, few reports about residual stress can be seen in the world, not to mentionin-depth research. On the other hand, how to control and reduce the residual stress tominimize the breakage caused by residual stress is an important problem must besolved.Now the main means on testing stresses are polariscope, X ray diffraction stressestesting instrument, neutron diffraction stresses testing instrument,ultrasonic stressestesting instrument and so on. In this study, X-ray diffraction,neutron diffractionmethod on residual stresses measurement was used. Then modern testing means wereused to test the properties and structure of CAS glass-ceramics, including XRD, andSEM, which was useful for elucidating what influence the residual stress in CASglass-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.Finally, the conclusions are as follows:1. The results of testing show that internal stresses in glass-ceramics could betested by X-ray diffraction and neutron diffraction. There were different magnitude ofstresses in glass-ceramics after annealing at different temperature, and the stresseschanged from compressive stress to tensile stress with the decrease of annealingtemperature. Especially, there were both the tensile stress and compressive stress inglass-ceramics when the annealing temperature was at 850℃. Thus, we couldsuitably control the annealing heat-treatment to shorten the glass-ceramics producingperiod without changing the property of the glass-ceramics. For example, we couldrapidly cool the glass-ceramics at the temperature above 850℃after crystallization.2. Theβ-wollastonite content changed from 26.27% to 37.52% when CaOcontent increased, but ratio of length vs diameter and bending strength decreased. Thestress changed from -463.2MPa to -333.9 MPa firstly, then increased to -959.9 MPawhen the CaO content changed from 15wt% to 17wt%.The change is due to both thecontent and size ofβ-wollastonite. In this study, the reasonable content of CaO isbetween 16wt% and 18wt%.3. For the Al2O3 restrain the growth ofβ-wollastonite in glass-ceramics, Soβ-wollastonite content decreased from 35.72% to 26.1% when the Al2O3 increased, andthe ratio of length vs diameter increased, the shape ofβ-wollastonite changed fromhistogram to acerose form. However, the bending strength increased firstly and thendecreased, the value of stress decreased from -837.3MPa to -364.2MPa, The changeis due to the contentβ-wollastonite and CTE of glass. So the optional content forAl2O3 is from 6wt% to 8wt%.4. Theβ-wollastonite content increased when glass granule minished, for theCTE ofβ-wollastonite is less than CTE of glass, so the large dismatch between theβ-wollastonite and glass and the value of compressive stress is from -146MPa to-218.571MPa.Otherwise,β-wollastonite distributed uniformity and conbined withglass more compact when the diameter of glass granule are between 0.5mm and1.5mm.5. Stress have studied with different thickness glass-ceramics without changing composition. Result showed that compressive stress changed from -45.8MPa to-444.1MPa when glass thickness increased. For the surface of glass was in contactwith the flowing gas and thus cooled much more rapidly, while the surface below wasin contact with fire-resistant material and cooled relatively slowly. Therefore, it iseasy to produce the compressive stress on the surface of the sample for thetemperature difference after annealing. Furthermore, when we changed the thicknessof the sample, the temperature more difference between the surface and below ofthe sample. So the optional thickness is between 18mm and 20mm.6. In this paper, the results showed that the stress line was fitted with the leastsquare calculator, in other ways, it means that error of measurement decreased whenwe increase diffraction angle and prolong diffraction time. Transmission depth ofneutron is millimeters relative to 0.01millimeter of X-ray diffraction, therefore, itmeans that neutron diffraction testing method will not be effected with surface ofsamples. The accuracy of stress close to 10-4 with neutron diffraction, so microstrainof glass can be tested accurately.
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