Effect of Indenter Elastic Modulus on Hertzian Ring Crack Initiation in Silicon Carbide
Effect of Indenter Elastic Modulus on Hertzian Ring Crack Initiation in Silicon Carbide
复制标题
压头弹性模量对碳化硅赫兹环裂纹萌生的影响
DOI：
10.1111/j.1744-7402.2010.02522.x
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发表时间：
2011
影响因子：
3.9
通讯作者：
O. Jadaan
中科院分区：
文献类型：
--
作者：
A. Wereszczak;W. Daloz;K. Strong;O. Jadaan
研究了球形压头刚度对热压碳化硅（SiC）中赫兹接触诱导断裂起始的影响。使用氧化锆、钢、氮化硅、氧化铝或碳化钨球形压头（弹性模量范围在213和630 GPa之间）测量赫兹环裂纹引发力。两个（平面靶）SiC是完全致密的，并且具有相等的弹性模量（~450 GPa）和断裂韧性;然而，一个SiC中约20%的晶粒大于另一个中的最大晶粒。降低压头弹性模量一致导致较低的环裂纹萌生力，这些差异具有统计学意义。随着压头弹性模量的降低，赫兹环裂纹萌生力的这种降低表明存在非零摩擦系数。此外，独立的压头材料，环裂纹萌生发生在较低的赫兹压痕力的SiC含有较大的晶粒，这表明在该尾部的晶粒尺寸分布作为格里菲斯型缺陷的晶粒。最后，选择具有与目标材料相同或相似的弹性模量的球形压头材料提供更简单的解释，并且以更大的有用性和保真度估计环裂纹萌生应力。这样的“匹配”条件用于规避在赫兹环裂纹起始应力的估计中普遍更未知的摩擦系数引入的复杂性。«少
The effect of spherical indenter stiffness on Hertzian-contact-induced fracture initiation was examined in hot-pressed silicon carbides (SiCs). Hertzian ring crack initiation forces were measured using zirconia, steel, silicon nitride, alumina, or tungsten carbide spherical indenters (elastic moduli ranging between 213 and 630 GPa). The two (flat target) SiCs were fully dense, and had equivalent elastic moduli (~450 GPa) and fracture toughnesses; however, about 20% of the grains in one SiC were larger than the largest grains in the other. Decreasing the indenter elastic modulus consistently resulted in lower ring crack initiation forces and those differences were statistically significant. Such a decrease in Hertzian ring crack initiation force with decreased indenter elastic modulus indicates the presence of a non-zero friction coefficient. Additionally, independent of the indenter material, ring crack initiation occurred at lower Hertzian indentation forces in the SiC containing larger grains suggesting that the grains in that tail of the grain-size-distribution acted as Griffith-type flaws. Lastly, selecting a spherical indenter material that has the same or similar elastic modulus as the target material provides simpler interpretation, and estimates of ring crack initiation stresses with greater usefulness and fidelity. Such a "matched" condition serves to circumvent the complexities that a ubiquitouslymore » unknown coefficient of friction introduces in the estimation of Hertzian ring crack initiation stress.« less