Glasses with Fictive Temperature-Independent Properties

具有虚拟温度无关特性的玻璃

• 批准号: 0804043
• 负责人: Minoru Tomozawa
• 金额: $ 48.82万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804043&HistoricalAwards=false
• 关键词: Glasses; Fictive; Temperature; Independent; Properties

NON-TECHNICAL DESCRIPTION: In general, properties of a glass vary depending upon how fast it was cooled from its melt. There are two different types of glasses: normal glass and anomalous glass and they exhibit the opposite cooling rate dependences of properties. Thus, between these two types of glasses with opposite trends, there should be some special glasses whose properties do not change with cooling rate. These glasses are expected to be useful in many applications. For example, a flat panel display screen made of such glasses would not change its volume during the heat-treatment and electrodes can be placed at precise positions, leading to clearer images on the screen. When a glass is scratched with a hard object, a portion of the glass appears to change its structure and properties, which can lead to easy cracking. The special glass to be investigated in this research appears not to change its properties during scratching and is consequently less likely to crack. One graduate student and two undergraduate students will be trained in this program. At least one of the three students will be female.TECHNICAL DETAILS: Glass prepared under different cooling rates is defined in terms of its fictive temperature, i.e., the temperature at which the liquid freezes into the glassy state. Glasses with fictive temperature-independent properties are expected to exhibit unique characteristics useful in practical application such as non-compaction during liquid crystal display glass processing. Diamond indentation is often used to characterize mechanical properties of glasses, but what is happening during indentation is not clear. It appears that fictive temperature of a glass increases during indentation and the fictive temperature dependence of glass properties plays an important role in mechanical behavior under indentation. Thus, this study of the proposed glasses is expected to lead to the development of glasses with unique properties and clarify what is occurring during indentation in glasses and other brittle materials.

非技术描述：一般而言，玻璃的性质因其从熔体中冷却的速度而异。有两种不同类型的眼镜：正常玻璃和异常玻璃，它们表现出相反的冷却速率依赖性。因此，在这两种类型的具有相反趋势的眼镜之间，应该有一些特殊的眼镜，其特性不会随冷却速率而变化。这些眼镜有望在许多应用中有用。例如，由此类眼镜制成的平板显示屏不会在热处理期间改变其体积，并且可以将电极放置在精确的位置，从而在屏幕上产生更清晰的图像。当玻璃用硬物体刮擦时，一部分玻璃似乎会改变其结构和特性，这可能会导致易于破裂。在这项研究中要研究的特殊玻璃似乎不会在刮擦过程中改变其特性，因此破裂的可能性较小。一名研究生和两名本科生将接受该计划的培训。三个学生中至少有一个是女性。技术细节：根据其虚拟温度（即液体冷冻到玻璃状状态的温度）定义了在不同冷却速率下制备的玻璃。具有虚拟温度独立特性的玻璃预计将表现出独特的特征，可用于实际应用，例如液晶显示器玻璃处理过程中的非复杂性。钻石压痕通常用于表征玻璃的机械性能，但是在压痕过程中发生的事情尚不清楚。看来玻璃的虚拟温度在压痕过程中升高，并且玻璃特性的虚拟温度依赖性在压痕下的机械行为中起着重要作用。因此，这项对拟议玻璃的研究有望导致具有独特特性的玻璃的发展，并阐明玻璃和其他脆性材料的压痕期间发生了什么。