3 GPa熔融盐固体介质三轴高温压力容器的轴压摩擦力标定

 在温度标定和围压标定的基础上，采用轴压循环方法，对3 GPa固体介质三轴高温高压实验系统的轴压摩擦力进行了标定，分析了围压、温度、轴向位移速率、装样方式（盐套类型）等实验条件对轴压摩擦力的影响。结果表明：静摩擦力、挤压摩擦力和滑动摩擦力3种轴压摩擦力对轴向应力的影响不同，其中静摩擦力和挤压摩擦力对轴向应力的影响很小，影响应力精度的主要是滑动摩擦力。静摩擦力及滑动摩擦力与围压正相关；静摩擦力与轴向位移速率正相关，但受其影响较小，滑动摩擦力不受其影响；静摩擦力和滑动摩擦力与温度负相关，并且受其影响较显著；盐套类型对轴压摩擦力的影响较大，当实验条件接近盐套熔点时，轴压摩擦力显著降低，当样品周围的盐套处于熔融状态时，轴压摩擦力最小。基于此，确定了标定轴压摩擦力的具体步骤，并对角闪岩的应力-应变曲线进行了轴压摩擦力标定。对比轴压摩擦力校正前、后的应力-应变曲线发现，经过轴压摩擦力校正的应力-应变曲线能更好地反映样品的实际变形情况。

Axial Friction Calibration for 3 GPa Molten Salt Medium Triaxial Pressure Vessel under High Pressure and High Temperature

The axial friction calibration of 3 GPa molten salt medium triaxial pressure vessel under high pressure and high temperature is performed based on the calibration of the temperature and confining pressure of the apparatus, which mainly analyses the effects from different experimental conditions, such as the confining pressure, the temperature, and type of salt cell used around the sample. The results show that the axial friction includes static friction, squeezing friction and sliding friction between the piston and the surrounding material. Three types of friction play different roles in axial stress, in which sliding friction is the main factor that affects axial stress precision, while static fiction and squeezing friction have little effects on axial stress. The static and sliding frictional force has a positive correlation to the confining pressure. The axial piston velocity has a positive effect on static friction, too, but the effect is not significant, while it has no effect on sliding friction. Both static and sliding friction has a negative correlation to the experimental temperature, and the effect of temperature is significant. The type of salt cell has a great effect on axial friction. The axial friction drops dramatically as the experimental temperature approaches the melting point of the salt. The procedure of calibrating axial friction is made based on the results, and the axial friction calibration is applied to stress-strain curves for deformation experiments of amphibole. It is found that it is more reliable that the deformation curve with the calibration of axial friction than the curve without calibration.