Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics
Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics
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DOI：
10.1016/j.jeurceramsoc.2017.09.013
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发表时间：
2018-02-01
影响因子：
5.7
通讯作者：
Fahrenholtz, W. G.
中科院分区：
文献类型：
--
作者：
D'Angio, A.;Zou, J.;Fahrenholtz, W. G.
研究了ZrC对ZrB2陶瓷在室温至2000℃范围内力学响应的影响。与之前报道的名义纯ZrB2相比，含有10 vol% ZrC的二硼化锆陶瓷在所有温度下都具有更高的强度。由于残余热应力的存在，ZrC的加入也使ZrB2的断裂韧性从3.5 MPa根m提高到4.3 MPa根m。在1600℃时，ZrC的韧性与ZrB2相当，但在1800℃和2000℃时，韧性增加到4.6 MPa根m， 1600℃以上韧性的增加归因于ZrC在高温下的塑性。电子背散射衍射分析显示，在2000℃的拉伸区，ZrC晶粒沿[001]方向有很强的取向，这一现象在四点弯曲的快速断裂（十字位移率= 4.0 mm min(-1)）中没有被观察到。认为高温下的显微组织变化和塑性是导致ZrC超快取向的机制。
The effect of ZrC on the mechanical response of ZrB2 ceramics has been evaluated from room temperature to 2000 degrees C. Zirconium diboride ceramics containing 10 vol% ZrC had higher strengths at all temperatures compared to previous reports for nominally pure ZrB2. The addition of ZrC also increased fracture toughness from similar to 3.5 MPa root m for nominally pure ZrB2 to 4.3 MPa root m due to residual thermal stresses. The toughness was comparable with ZrB2 up to 1600 degrees C, but increased to 4.6 MPa root m at 1800 degrees C and 2000 degrees C. The increased toughness above 1600 degrees C was attributed to plasticity in the ZrC at elevated temperatures. Electron back-scattered diffraction analysis showed strong orientation of the ZrC grains along the [001] direction in the tensile region of specimens tested at 2000 degrees C, a phenomenon that has not been observed previously for fast fracture (crosshead displacement rate = 4.0 mm min(-1)) in four point bending. It is believed that microstructural changes and plasticity at elevated temperature were the mechanisms behind the ultrafast reorientation of ZrC.