AN EVALUATION OF THE GRAIN-BOUNDARY SLIDING CONTRIBUTION TO CREEP DEFORMATION IN POLYCRYSTALLINE ALUMINA
AN EVALUATION OF THE GRAIN-BOUNDARY SLIDING CONTRIBUTION TO CREEP DEFORMATION IN POLYCRYSTALLINE ALUMINA
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DOI：
10.1007/bf00587678
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发表时间：
1990-07-01
影响因子：
4.5
通讯作者：
CHOKSHI, AH
中科院分区：
文献类型：
--
作者：
CHOKSHI, AH
在四点弯曲模式下进行测试之前，通过在试样的拉伸表面上刻上标记线来检查细晶粒氧化铝在蠕变过程中晶界滑动的发生。蠕变变形过程中晶界滑动和晶粒旋转的发生有相当多的显微组织证据。对晶界标记线偏移量的实验测量表明，蠕变过程中晶界滑动对总应变的贡献为70 ± 6.2%。观察到的广泛的晶界滑动，连同其他机械性能，表明多晶氧化铝具有超塑性特性。几种可能的速率控制机制进行了严格审查，根据目前的结果，它的结论是蠕变发生由一个独立的晶界滑动机制或由界面控制的扩散机制。
The occurrence of grain-boundary sliding during creep in fine grained alumina was examined by inscribing marker lines on the tensile surfaces of specimens, prior to testing in four-point bending mode. There was considerable microstructural evidence for the occurrence of grainboundary sliding and grain rotation during creep deformation. Experimental measurements of the offsets in the marker lines at grain boundaries reveal that the grain-boundary sliding contribution to the total strain during creep deformation is 70 ± 6.2%. The extensive grain boundary sliding observed, together with the other mechanical properties, suggests that polycrystalline alumina exhibits superplastic characteristics. Several possible rate controlling mechanisms are examined critically in light of the present results and it is concluded that creep occurs either by an independent grain-boundary sliding mechanism or by an interface controlled diffusion mechanism.