Unusual Indentation Behavior of Alkali Metaphosphate Glass Above Glass Transition Temperature

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• 作者：Jun Endo ; Seiji Inaba ; Hiroyuki Muto and Setsuro Ito
• 刊名：Journal of the American Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：100
• 期：1
• 页码：81-85
• 全文大小：750K
• ISSN：1551-2916

文摘

The mixed alkali metaphosphate glass 12.5Li₂O–12.5Na₂O–12.5K₂O–12.5Cs₂O–50P₂O₅ (mol%) compressed under uniaxial stress shows unusually large recovery of its shape during heating above its glass transition temperature (T_g). To clarify the mechanism, the viscous, elastic, and plastic behavior of the metaphosphate glass was investigated with the depth-sensing indentation method. From the load-displacement (P–h) curves of the glass, a large recovery of the depth displacement was found during unloading above T_g. By analyzing the P–h curves with a viscous–elastic–plastic model, the large recovery was concluded to be due to larger elastic deformation than viscous deformation even above T_g. The phenomenon can be attributed to relaxation to the randomly oriented -P–O–P– chain structure from the oriented chain structure formed under stress in the metaphosphate glass.