Effect of grain orientation on the compressive response of highly oriented MAX phase Ti3SiC2
Effect of grain orientation on the compressive response of highly oriented MAX phase Ti3SiC2
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DOI：
10.1016/j.msea.2021.140869
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发表时间：
2021-02
期刊：
影响因子：
6.4
通讯作者：
Xingyuan Zhao;M. Sokol;M. Barsoum;L. Lamberson
中科院分区：
文献类型：
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作者：
Xingyuan Zhao;M. Sokol;M. Barsoum;L. Lamberson
MAX相由一组层状三元碳化物组成，具有独特的机械性能，可弥合金属和陶瓷成分之间的差距。为了研究晶粒的整体取向对材料性能的影响，采用Ti、Si和TiC粉末热压合成了高取向的Ti 3SiC 2块体材料。使用X射线衍射（XRD）来验证晶粒取向，并且获得相对于c轴为0.87的Lotgering因子。制备的Ti 3 SiC 2样品在两个方向上进行压缩，沿着c轴（α c轴）和垂直于c轴（α c轴）加载，使用标准载荷框架以10 - 3 s-1加载，使用Kolsky（split-Hopkinson）杆以10 2 s-1加载。沿轴向沿着的平均压缩强度在准静态条件下为761 MPa，在动态载荷下为987 MPa，表现出平均30%的增加。在抗压强度方面，α-轴取向没有表现出速率依赖性;然而，两个取向在动态条件下的失效应变平均增加超过0.5%。在加载过程中，通过扫描电子显微镜（SEM）尸检，使用高速成像和2D数字图像相关（DIC）在不同的应变率的取向相关的失效行为进行了研究。结果表明，在轴向断裂面上存在穿晶和沿晶裂纹、扭折带和分层，而在轴向断裂面上仅存在沿晶和穿晶裂纹。由于弯折带形成的可用性（或缺乏），这种断裂区别似乎是各向异性压缩行为的原因。
The MAX phases comprise of a group of layered ternary carbides that exhibit unique mechanical properties which bridge the gap between their metal and ceramic constituents. To study the effects of the global grain orientation, Ti, Si and TiC powders were hot pressed to synthesize highly oriented bulk Ti 3 SiC 2. X-ray diffraction (XRD) was used to verify the grain orientation and a Lotgering factor of 0.87 with respect to the c-axis was obtained. Prepared Ti 3 SiC 2 samples have been compressed in two orientations, loading along the c-axis (∥ c-axis) and perpendicular to the c-axis (⊥ c-axis) at 10− 3 s− 1 using a standard load frame and at 10 2 s− 1 using a Kolsky (split-Hopkinson) bar. The average compressive strength along the⊥ c-axis orientation was 761 MPa under quasi-static conditions and 987 MPa under dynamic loading, exhibiting a 30% increase on average. The∥ c-axis orientation exhibited no rate dependence in compressive strength; however both orientations exhibited an increase of strain at failure under dynamic conditions by over 0.5%, on average. The orientation-dependent failure behavior at different strain rates were examined using high-speed imaging and 2D digital image correlation (DIC) during loading and via scanning electron microscopy (SEM) post-mortem. Results indicate that the⊥ c-axis fracture surface exhibited a mixture of transgranular and intergranular cracks, kink bands and delaminations, whereas∥ c-axis was limited to a combination of intergranular and transgranular cracks. Such fracture distinctions due to the availability (or lack thereof) for kink band formation appear to be responsible for the anisotropic compressive behavior.