The presence of small amount of liquid at grain boundaries tends to form thin viscous layer which surrounds the finer grains . intergranular fracture may occur at the grain boundaries between two fine grains not covered by viscous phases . the high ductility achieved at low strain rates is generally attributed to dislocation glide - creep accommodation mechanisms 原始晶界上产生少量液相，形成薄的固液共存粘性层并包围细化的晶粒，沿晶断裂主要发生在无粘性层的细晶粒间；而在较低应变速率下，三叉晶界位错攀援?蠕变协调机制松弛晶界滑移产生的应力集中，晶界上产生较多液相，有利于晶界滑移进行。
