High temperature compressive creep of spark plasma sintered zirconium (oxy-)carbide
High temperature compressive creep of spark plasma sintered zirconium (oxy-)carbide
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DOI：
10.1016/j.msea.2014.06.059
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发表时间：
2014-08
期刊：
影响因子：
6.4
通讯作者：
G. Antou;Mathieu Gendre;E. Laborde;A. Maître;G. Trolliard
中科院分区：
文献类型：
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作者：
G. Antou;Mathieu Gendre;E. Laborde;A. Maître;G. Trolliard
考虑了化学计量比(即碳、氧含量)和显微组织(即微晶尺寸)对氧化碳化锆蠕变机制的影响。用碳还原法合成了化学计量比可控、无杂质的ZrCxO粉末。对放电等离子烧结得到的全致密碳化锆试件在1500~1600℃、60~140℃的外加应力下进行了压缩蠕变实验。氧含量较高的成分(即ZrC0.79O0.13)的蠕变抗力较低，而ZrC0.94O0.05成分的蠕变抗力较低。对蠕变数据的分析表明，存在线性蠕变极限(σt)。在低应力下(即σ≤σt=10 0≈，n≈1，m≈1)，蠕变机制似乎与化学成分无关，由锆体扩散控制。在高应力下(即σ≥σt=10 0 0≈，n≈3，m≈0)，蠕变呈现出幂函数规律。然而，蠕变过程的速率决定步骤的性质取决于化学计量比。体积扩散的限制物种是(I)金属原子(对于ZrC0.94O0.05)；(Ii)与Rowcliffe位错扩散机制相连的碳原子(对于ZrC0.79O0.13)。
The effect of stoichiometry (i.e. carbon and oxygen contents) and microstructure (i.e. micro-sized grains) on creep mechanism of zirconium oxycarbide was considered. The synthesis of ZrCxOypowder of controlled stoichiometry and without impurity has been performedviathe carboreduction route. Compressive creep experiments were conducted at 1500–1600 °C under applied stresses ranging from 60 to 140 MPa on fully dense zirconium oxycarbide specimens obtained by spark plasma sintering. The higher oxygen content composition (i.e. ZrC0.79O0.13) reveals low creep resistance in contrary to ZrC0.94O0.05composition. The analysis of the creep data shows the existence of a linear creep limit (σt). At low stress (i.e. σ≤σt=100 MPa,n≈1,m≈1), the creep mechanism seems to be independent of the chemical composition, and is governed by zirconium volume diffusion. At high stress (i.e. σ≥σt=100 MPa,n≈3,m≈0), a power law regime of creep appears. However, the nature of the rate-determining step of creep process depends on stoichiometry. The limiting species for volume diffusion are (i) the metal atom for ZrC0.94O0.05; (ii) and the carbon atom for ZrC0.79O0.13linked to a Rowcliffe dislocation diffusion mechanism.