Toughness Properties of a Silicon Carbide with an in Situ Induced Heterogeneous Grain Structure
Toughness Properties of a Silicon Carbide with an in Situ Induced Heterogeneous Grain Structure
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DOI：
10.1111/j.1151-2916.1994.tb04637.x
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发表时间：
1994-10
影响因子：
3.9
通讯作者：
N. Padture;B. Lawn
中科院分区：
文献类型：
--
作者：
N. Padture;B. Lawn
粗糙和细长的晶粒结构和晶间第二相的异质碳化硅的韧性特性进行评估相对于一个均匀的，细晶粒的控制，使用压痕强度数据。非均质材料表现出独特的缺陷容限，表明了明显的韧性曲线。数据的定量评估揭示了在长裂纹区域的韧性增强，在短裂纹区域的韧性退化的含义。长裂纹韧性的提高与裂纹界面桥接有关。短裂纹韧性的下降是由于弱化的晶粒或界面边界和内部残余应力的热膨胀失配。韧性曲线行为的一个深刻表现是赫兹接触中机械损伤性质的转变，从均匀控制中的经典单裂纹锥形断裂到非均匀材料中的分布亚表面损伤。
Toughness characteristics of a heterogeneous silicon carbide with a coarsened and elongated grain structure and an intergranular second phase are evaluated relative to a homogeneous, fine-grain control using indentation–strength data. The heterogeneous material exhibits a distinctive flaw tolerance, indicative of a pronounced toughness curve. Quantitative evaluation of the data reveals an enhanced toughness in the long-crack region, with the implication of degraded toughness in the short-crack region. The enhanced long-crack toughness is identified with crack-interface bridging. The degraded short-crack toughness is attributed to weakened grain or interface boundaries and to internal residual stresses from thermal expansion mismatch. A profound manifestation of the toughness-curve behavior is a transition in the nature of mechanical damage in Hertzian contacts, from classical single-crack cone fracture in the homogeneous control to distributed subsurface damage in the heterogeneous material.