The Uniaxial Stress Measurements Under High Pressure: Application to Geophysics

高压下的单轴应力测量：在地球物理学中的应用

• 批准号: 8905227
• 负责人: Yosiko Sorensen
• 金额: $ 6.33万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-11-15 至 1992-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8905227&HistoricalAwards=false
• 关键词: Uniaxial; Stress; Measurements; Under; Pressure

This is a project to develop a novel new x-ray diffraction technique to determine the stress distribution under in-situ high pressure conditions corresponding to the mantle interior. With this technique, studies such as stress-induced preferred orientation and yield strength measurements of high-pressure minerals, which are necessary to further understand the dynamics of the mantle, will become possible. These measurements can be made either in multi-anvil high pressure apparatus or in diamond anvil cells. A reliable method to determine the uniaxial stress under high pressure by measuring the anisotropic compression of standard materials using the new high-precision x-ray diffraction technique will be established. This technique will be applied to study the stress-induced preferred orientation in beta-Mn2GeO4 (chosen as a model system for the (Mg-Fe)SiO4 mantle olivine) as it undergoes the polymorphic transformation from its olivine- phase to beta-phase under the influence of uniaxial stress. The PI will apply the new technique to study the changes in the yield strength of alkali halides across the B1-B2 phase boundary, to look for possible superplasticity at the transition and to determine the elastic constants of the B2 phase. The experiments will be conducted in collaboration with four Japanese high- pressure scientists using the MAX-80 cubic-anvil high-pressure system stationed at the high-energy (maximum - 140KeV) synchrotron radiation x-ray source at the national Laboratory for High Energy Physics in Tsukuba, Japan.

这是一个开发一种新的X射线衍射技术来确定与地幔内部相对应的现场高压条件下的应力分布的项目。有了这项技术，高压矿物的应力诱导择优取向和屈服强度测量等研究将成为可能，这是进一步了解地幔动力学所必需的。这些测量既可以在多砧高压装置中进行，也可以在金刚石砧室中进行。利用新的高精度X射线衍射技术，通过测量标准材料的各向异性压缩，将建立一种可靠的方法来确定高压下的单轴应力。这项技术将用于研究β-Mn2GeO4(被选为(Mg-Fe)SiO4地幔橄榄石的模型体系)在单轴应力作用下经历从橄榄石相到β相的多晶性转变时的应力诱导择优取向。PI将应用这项新技术来研究碱金属卤化物在B1-B2相界上屈服强度的变化，寻找转变时可能的超塑性，并确定B2相的弹性常数。这些实验将与四名日本高压科学家合作进行，使用的是驻扎在日本筑波国家高能物理实验室高能(最高-140KeV)同步辐射X射线源上的MAX-80立方顶锤高压系统。