Rheology of grain-boundary sliding and grain interlocking

(1)设计并建造了一套新型的高温（500 ~ 1300 ℃）流变试验系统。(2)本文对多晶材料在不同类型的多轴应力/应变场中的晶界熔体相粘弹性本构方程进行了理论分析和定量推导。该方程包含了多晶晶粒的弹性变形和熔体相在晶粒通道中的粘性流动。(3)提出了一种新的耐火材料颗粒集料超塑性变形的微观结构模型。集体中的颗粒群的合作运动的重要性被强调为包括在拉伸/压缩下的大规模变形是必不可少的。对超塑性变形的尺寸效应规律作出了重要的理论预测。(4)利用ZrO_2陶瓷进行了各种流变试验，试验结果与晶界Zener松弛、晶粒互锁、晶界协同滑动等微观过程和机制有关。(5)从理论上研究了锥形压痕产生的时间相关粘弹性表面变形，推导了微观表面接触的本构方程。(6)一种新型的压痕测试系统，在高温下（从300至1500摄氏度）的设计，建造，并应用于流变测试各种类型的无机玻璃以上的玻璃化转变点。

(1) A novel rheological test system which operates at high temperatures (ranging from 500 to 1300 degree centigrade) was designed and constructed.(2) Theoretical considerations and quantitative derivations were made for the viscoelastic constitutive equations of polycrystals with grain-boundary melt-phase in various types of multiaxial stress/strain fields. The equations include the elastic deformation of respective polycrystalline grains, as well as viscous flow of melt-phase in grain channels.(3) A novel microstructural model for the superplastic deformation of refractory grain aggregates was proposed. The importance of cooperative motions of groups of grains in an aggregate was emphasized to be essential for including a large-scale deformation under tension/compression. An important theoretical prediction for a size-effect law in superplastic deformation was made.(4) Various types of rheological test were conducted by the use of ZrO2-ceramics, and the test results were related to the microscopic processes and mechanisms of grain-boundary Zener-relaxation, grain interlocking, cooperative grain-boundary sliding.(5) Time-dependent viscoelastic surface deformation produced by a pyramidal indentation was theoretically examined to derive a constitutive equation for a microscopic surface contact.(6) A novel indentation test system that operates at elevated temperatures (from 300 to 1500 degree centigrade) was designed, constructed, and applied to rheologically testing various types of inorganic glasses above their glass transition points.