Micromechanical properties of WC-(W,Ti,Ta,Nb)C-Co composites
Micromechanical properties of WC-(W,Ti,Ta,Nb)C-Co composites
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DOI：
10.1016/j.jallcom.2018.11.001
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发表时间：
2019-03
影响因子：
6.2
通讯作者：
D. Sandoval;J. Roa;O. Ther;E. Tarrés;L. Llanes
中科院分区：
文献类型：
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作者：
D. Sandoval;J. Roa;O. Ther;E. Tarrés;L. Llanes
深入了解硬质合金各组成相的微观力学性能是在优化组织设计的基础上提高其性能的关键。在目前的工作中，一个系统的实验程序已被遵循，以确定个别WC和（W，Ti，Ta，Nb）C颗粒的固有硬度，以及金属粘结剂，内的WC-Co复合材料含有混合碳化物的固溶体作为第三相。在这样做的过程中，大量的纳米压痕和收集的数据的统计分析相结合。结果表明，（W，Ti，Ta，Nb）C颗粒的硬度明显高于WC颗粒，与WC颗粒的硬度各向异性无关。金属粘合剂的硬度评估需要进一步分析，包括使用薄膜模型的数据解卷积和考虑基底效应。获得的硬度值然后用于通过塔博尔方程估计金属相的有效流动应力，得到1.3和2.0 GPa之间的值。这些高约束相关的值最终验证的应力水平的实验评估，在该应力水平下，应变爆发被确定在通过单轴压缩的微柱获得的应力-应变曲线。
A deep knowledge of micromechanical properties of each constitutive phase of cemented carbides is crucial to improve their performance on the basis of microstructural design optimization. In the present work, a systematic experimental procedure has been followed to determine the intrinsic hardness of individual WC and (W,Ti,Ta,Nb)C particles, as well as that of the metallic binder, within a WC-Co composite containing a solid solution of mixed carbide as a third phase. In doing so, massive nanoindentation and statistical analysis of the gathered data are combined. Results showed that (W,Ti,Ta,Nb)C particles are significantly harder than WC ones, independent of the hardness anisotropy exhibited by the latter. Hardness assessment for the metallic binder required further analysis, including data deconvolution using thin film models and consideration of substrate effects. The attained hardness values are then used for estimation of effective flow stress of the metallic phase by means of Tabor's equation, yielding values ranging between 1.3 and 2.0 GPa. These high constraining-related values are finally validated by experimental assessment of stress levels at which strain bursts are identified in stress-strain curves obtained by uniaxial compression of micropillars.