微粒对多晶冰流变行为的影响(Ⅰ):应力下的流变行为

研究了应力下微粒对多晶冰流变行为的影响.结果表明:微粒分布在晶界或同时分布在晶界和晶内都将增加多晶冰的流变速率.当微粒只分布在晶界时,含微粒浓度为1 wt.%的多晶冰有最高的最小流变速率;当微粒同时分布在晶内与晶界时,多晶冰的最小流变速率基本与微粒浓度无关.微粒提高流变速率的原因来源于提高了流变过程中的位错密度,分布在晶界和晶内的微粒可以分别通过阻碍晶界滑移,发展内应力及Frank-Read位错增值机制提高流变过程中的位错密度.

Effect of Fine Particles on the Flow Behavior of Polycrystalline Ice(I):Flow behavior under stress

The effect of fine particles on the flow behavior of polycrystalline ice under stress has been studied.It has been shown that particles increase the flow velocity no matter whether the particles distribute only along the grain boundaries or both along the grain boundaries and inside grains.The ice with 1 wt.% particles has the highest minimum flow velocity when the particles distributed only along the grain boundaries.However,the minimum flow velocity is roughly independent of particle concentration when particles distributed both along the grain boundaries and inside the grains.The high flow velocity for ice with particles is due to the high dislocation density.The particles can increase the dislocation density by inhibiting the grain boundary sliding and developing internal stress when distributed along the grain boundaries,and by Frank-Read mechanism when distributed both along the grain boundaries and inside the grains.