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首页> 外文会议>Advanced processing and manufacturing technologies for structural and multifunctional materials V >DENSIFICATION MECHANISMS OF YTTRIA-STABILIZED ZIRCONIA BASED AMORPHOUS POWDERS BY ELECTRIC CURRENT ASSISTED SINTERING PROCESS
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DENSIFICATION MECHANISMS OF YTTRIA-STABILIZED ZIRCONIA BASED AMORPHOUS POWDERS BY ELECTRIC CURRENT ASSISTED SINTERING PROCESS

机译：电流辅助烧结过程对氧化钇稳定氧化锆基非晶粉的致密化机理

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摘要

Rapid densification behaviors (relative density; ρ<0.92) of mechanically milled 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) and 3Y-TZP containing 20 mol% boron powders by electric current activated/assisted sintering have been investigated. Although the starting 3Y-TZP powder was amorphous, the crystallization of tetragonal zirconia solid solution (t-ZrO_(2ss)) was completed before the appearance of rapid densification, indicating the impracticability of densification via amorphous viscous flow. The n (stress exponent) values estimated by a hot-pressing kinetic equation increase with decreasing effective stress (i.e., increasing p), but n recalculated by taking into consideration the threshold stress (σ_0) show almost the constant value of 2. These recalculated values are quite similar to those of creep deformation with an accompanying σ_0 in the intermediate-stress region, suggesting that the rapid densification behavior is controlled by grain boundary sliding. The addition of boron changes the densification behavior drastically. The estimated n values without considering σ_0 show n=1.35 in the low temperature region (T: 1120 K.) and n=2 in the high temperature region (T>1120 K), suggesting that the boron-rich glassy phase coexisting with tetragonal (monoclinic at room-temperature) ZrO_(2ss) may relieve the stress concentration generated by grain boundary sliding of the matrix ZrO_(2ss) grains.
机译：通过电流活化/辅助烧结研究了机械研磨的3摩尔％的氧化钇稳定的四方氧化锆多晶（3Y-TZP）和含20摩尔％的硼粉的3Y-TZP的快速致密化行为（相对密度；ρ<0.92）。尽管起始的3Y-TZP粉末是无定形的，但四方氧化锆固溶体（t-ZrO_（2ss））的结晶在出现快速致密化之前已经完成，这表明通过无定形粘性流进行致密化是不可行的。通过热压动力学方程估算的n（应力指数）值随有效应力的减小（即p增大）而增加，但考虑到阈值应力（σ_0）重新计算的n几乎显示为常数2。值与中应力区伴随σ_0的蠕变变形非常相似，这表明快速致密化行为受晶界滑动控制。硼的添加极大地改变了致密化行为。在不考虑σ_0的情况下估算的n值在低温区域（T：1120 K.）中显示n = 1.35，在高温区域（T> 1120 K）中显示n = 2，这表明富硼玻璃相与四方晶共存。 （在室温下为单斜晶）ZrO_（2ss）可以缓解基体ZrO_（2ss）晶粒的晶界滑动所产生的应力集中。

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