Dynamic wetting of solid-liquid composites and its effects on the mechanical properties

1、通过模拟部分熔岩的变形实验，验证了应力作用下各向异性微结构的发展。2、从微观结构的角度出发，从理论上推导了部分熔岩在晶界扩散蠕变变形过程中的粘性本构关系。本研究中建立的粘性本构关系是基于邻接性作为内部状态变量的，这使得我们能够考虑实验中观察到的颗粒尺度熔体分布的详细影响。3、与先前针对相同微观结构模型推导的弹性相比，粘性对熔体的存在和邻接性的变化更加敏感。极少量的熔体(&lt；0.01)显著降低了体积粘度和剪切粘度，这对熔体分离动力学具有重要意义。4、在部分熔岩变形中，连续各向异性产生了很大的粘性各向异性。5、在各向异性粘度下，剪切应力和各向同性应力之间发生了直接耦合，因此剪切变形在熔体迁移中的作用显著增加。在两种简单的情况下，我们展示了粘性各向异性对熔体迁移动力学的显著影响。首先，在旋转剪切变形中，各向异性为熔体沿固体基质中的应力梯度向上迁移创造了驱动力。其次，在均匀的简单剪切变形中，由于熔体的各向异性排列，熔体自发偏析成小角度带。6、当应用于俯冲带地幔楔形流动的简单近似时，各向异性本构关系显著影响熔体的迁移模式。

1, From the deformation experiment of partially molten rock analogue, development of anisotropic microstructure under stress was demonstrated.2, Viscous constitutive relations of partially molten rocks deforming in the regime of grain boundary (GB) diffusion creep are derived theoretically based on microstructural processes at the grain scale. The viscous constitutive relation developed in this study is based on contiguity as an internal state variable, which enables us to take into account the detailed effects of grain-scale melt distribution observed in experiments.3, Compared to the elasticities derived previously for the same microstructural model, the viscosities are much more sensitive to the presence of melt and variations in contiguity. A very small amount of melt (<0.01) significantly reduces the bulk and shear viscosities, which has important implications for melt segregation dynamics.4, A large viscous anisotropy is produced by anisotropy in contiguity, which occurs in deforming partially molten rocks.5, With anisotropic viscosity, a direct coupling between shear and isotropic components of stress occurs and hence the role of shear deformation in melt migration significantly increases. We demonstrate the significant effects of viscous anisotropy on melt migration dynamics for two simple cases. First, in rotary shear deformation, an anisotropy creates a driving force for melt migration up stress gradients in the solid matrix. Second, in uniform simple shear deformation, melt segregates spontaneously into low-angle bands due to anisotropic melt alignment.6, When applied to a simple approximation of flow in the mantle wedge of subduction zone, the anisotropic constitutive relation significantly affects melt migration patterns.