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通过光学显微镜及单轴压缩的方法,研究了不同应力和温度下微粒对多晶冰流变过程中显微组织演变的影响.研究表明:不论高温还是低温,或者高应力还是低应力,含微粒的多晶冰总是有较高的流变速率.在-10℃及1.45 MPa的应力下,两种冰在流变过程中的动态再结晶通过新生晶粒沿晶界的形核及长大完成.由于微粒在流变过程中通过阻碍晶界滑移而发展高的内应力,含微粒的多晶冰有较高的动态再结晶速率,其晶粒尺寸远小于不含微粒的多晶冰的晶粒尺寸.在-5℃、-10℃及0.4 MPa的应力下,由于微粒在流变过程中同样通过阻碍晶界滑移而发展较高的内应力,含微粒的多晶冰在流变过程中的动态再结晶仍然通过新生晶粒沿晶界的形核及长大完成.而对于不含微粒的多晶冰,由于流变应力较低,晶界应变能不足以诱发新生晶粒的形核,因此动态再结晶通过应变诱发的晶界迁移完成,其结果是晶粒的尺寸保持不变.
The effect of particles on the microstructure evolution of polycrystalline ice under different stress and temperature was studied by means of optical microscope and uniaxial compression method. The results show that, whether high temperature or low temperature, high or low stress, Of the polycrystalline ice always has a higher rheological rate.The dynamic recrystallization of the two kinds of ice during the rheological process at the temperature of -10 ℃ and 1.45 MPa is verified by the nucleation and growth of the new grain along the grain boundary Since the microparticles develop high internal stresses by hindering the grain boundary slip during rheology, polycrystalline ice with microparticles has a higher dynamic recrystallization rate and is much smaller in grain size than the polycrystalline ice without microparticles At temperatures of -5 ° C, -10 ° C and 0.4 MPa, as microparticles develop a higher internal stress during the rheological process by also hindering the grain boundary slip, the polycrystalline ice containing particles flows in a stream Dynamic recrystallization in the process of transformation is still accomplished by the nucleation and growth of newborn grains along the grain boundaries, whereas for polycrystalline ice not containing particles, the grain boundary strain can not be enough to induce new grain due to lower flow stress The dynamic recrystallization is completed by strain-induced grain boundary migration As a result, the grain size remains the same.