| 其他摘要 | 大量证据表明，地球内部物质除受到各向同性的静水压力作用外，在其上还广泛叠加有差异应力的作用。差异应力对物质的自由能具有重要贡献，而自由能却是控制物质体系组成、结构、构造、性状及相互作用过程的决定性因素。因此，差异应力与温度和静水压力一样，其是约束地球内部物质体系最基本的热力学变量之一。然而，以往人们对地球内部物质的高温高压实验研究，由于高温高压设备与原位测量技术受限，除专门的应力-应变力学实验和少部分压溶及动力变质实验外，基本上未涵盖差异应力的作用，由此使得人们迄今从高温高压实验所获得的有关地球内部物质的很多认识普遍存在质疑。下部地壳至上地幔上部是地球内部极为重要的圈层。目前，可用于模拟该深度范围的温度、静水压和差异应力的高温高压实验平台主要包括Griggs型压机、D-DIA型压机和压扭型金刚石压腔等三种高温高压实验装置。然而，Griggs型压机在高温下可模拟的最高静水压仅2 GPa左右；而D-DIA型压机模拟该深度范围内静水压的精度有限，且差异应力的标定存在较大的不确定性；压扭型金刚石压腔则存在样品小、压力标定困难且工作温度不高的问题。为此，亟需在多面顶大腔体压力机上研发一套可覆盖室温-1000 ℃、0-4.0 GPa温压范围、能方便与各种原位测量技术对接的差异应力发生装置。作为差异应力发生装置的一部分，本硕士学位论文工作通过高温下MnCu丝的压阻效应，开展差异应力组装腔体围压标定工作，圆满地解决了基于DS6×1400 t大腔体压力机的差异应力发生装置中不同温度下固体试件的围压原位测量问题。主要成果包括：（1）通过使用高精度LVDT位移传感器，对DIA型六面顶大腔体压力机（YJ-3000 t）和铰链式六面顶大腔体压机（DS6×1400 t）对向顶砧之间的距离与油压荷载之间的关系进行了反复测量。结果发现，DS6×1400 t 大腔体压力机对向顶砧之间的距离与油压荷载之间有单调、可重复的线性关系，证实了DS6×1400 t 大腔体压力机更适合本次研究。（2）通过氯化盐的高压熔融实验以及在常温高压下对MnCu丝电阻的原位测量，系统准确地标定了不同温度下DS6×1400 t大腔体压力机样品腔内的压力，成功地获得了不同温度下压力机油压荷载与样品腔内实际压力的定量关系。（3）基于DS6×1400 t 大腔体压力机，首次在不同温度以及不同油压荷载下原位测量了MnCu丝的电阻。结果发现，在常温下油压荷载与MnCu丝电阻之间呈线性关系的特征在高温下同样存在。（4）基于该论文工作中所获得的不同温度下DS6×1400 t压力机油压荷载与样品腔内实际压力的定量关系，以及在不同温度下DS6×1400 t压力机油压荷载与MnCu丝电阻之间的线性关系，首次成功地实现了在高温下利用MnCu丝的压阻效应原位标定DS6×1400 t压力机样品腔内的压力。上述研究成果为未来在DS6×1400 t多面顶大腔体压力机上研发一套实际可用的差异应力发生装置奠定了极为重要的基础。; A large amount of evidences show that the materials in the earth’s interior is not only affected by the isotropic hydrostatic pressure, but also has the effect of differential stress. The differential stress plays an important role in the free energy of materials, and the free energy is the decisive factor to control the composition, structure, character and interaction process of materials. Therefore, the differential stress is the same as the temperature and hydrostatic pressure, which is one of the most basic thermodynamic variables that can constrain the materials of earth’s interior. However, due to the limitation of high temperature and high pressure and in-situ measurement technology, the previous researches on high temperature and high pressure experiments of the earth's interior, which don’t cover the effect of differential stress in addition to the stress-strain mechanical experiment and a small part of the pressure solution and dynamometamorphic special experiment. The results of high temperature and high pressure experiments are questioned. The lower crust to the uppermost in the upper mantle is an extremely important sphere in the earth's interior. At present, there are three kinds of high temperature and high pressure experimental equipments can be used to simulate the temperature, hydrostatic pressure and differential stress of this sphere, It mainly includes Griggs type press, D-DIA type press and diamond anvil chamber. However, the maximum hydrostatic pressure of the Griggs type press is only about 2 GPa at high temperatures, the accuracy of hydrostatic pressure of D-DIA type press is limited and there is a great deal of uncertainty about the calibration of differential stress, the diamond anvil cell has some problems, such as small sample, difficult pressure calibration and low operating temperature.It is necessary to invent a differential stress device which can cover the temperature from the room temperature to 1000 degrees centigrade, the pressure from 0 to 4.0 GPa and be conveniently connected with various in-situ measurement technology in large volume press apparatus.As a part of differential stress device, my thesis is based on the piezoresistive effect of MnCu wire at high temperature to carry out the confining pressure of the deferential stress assemble. We successfully solve the in-situ measurement of the confining pressure of the solid sample at different temperatures in the differential stress generating device based on DS6×1400 t large volume press apparatus(LVP). The main experimental results are as follows:(1) By using a high-precision Linear Variable Differential Transformer (LVDT) displacement sensor, we repeatedly measure the relationship between the the oil pressure and the counterpart anvil distance of YJ-3000 t LVP and the DS6×1400 t LVP. Findings, the relationship between the oil pressure and the counterpart anvil distance of DS6×1400 t LVP is more regular, it is confirmed that the DS6×1400 t LVP is more suitable for this study.(2) By the high pressure melting experiments of chloride and in-situ measurement of MnCu wire resistance at room temperature and high pressure, the pressure in the capsule of DS6×1400 t LVP at different temperatures is calibrated accurately, the quantitative relationship between the oil pressure and the actual pressure in the capsule at different temperatures is obtained successfully.(3) Based on DS6×1400 t LVP, the resistance of MnCu wire is firstly in-situ measurement at different temperature and different oil pressure. It is found that the linear relationship between the oil pressure and the resistance of MnCu wire at room temperature is also present at high temperature.(4) Based on the relationship between the oil pressure and the actual pressure in the capsule of DS6×1400 t LVP at different temperatures and the linear relationship between the oil pressure and the resistance of MnCu wire at different temperature, piezoresistive effect of MnCu wire is firstly used to complete in-situ measurement the chamber pressure of DS6×1400 t LVP at high temperature condition.The results of this thesis lay the very important foundation to invent differential generating device on the DS6×1400 t large volume press apparatus in the future. |
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