Mazerat S, Pailler R
Univ. Bordeaux, CNRS, CEA, SAFRAN CERAMICS, LCTS, UMR 5801, F-33600 Pessac, France.
Data Brief. 2020 Dec 24;34:106676. doi: 10.1016/j.dib.2020.106676. eCollection 2021 Feb.
This data article reports a systematic fractographic analysis of SiC-based filaments aiming at stress intensity factors assessment. A total of 11 fiber types (as-received or chlorinated Nicalon® and Tyranno® of all three generations) where therefore repeatedly tensile tested to generate the fracture surfaces. The tensile strengths were found to be independent to defect location (surface or internal). The well-known linear square root dependence of strength on mirror, mist or hackle outer radius was reaffirmed. These measurements reveal some residual tensile stresses on Nicalon® fibers, statement however questioned by the broad data scattering. Moreover, it is shown the surface etching treatment didn't affected (generating or releasing) such residual stress. A null -intercept was consequently adopted to assess the characteristic stress intensity factors ( , mirror, mist or hackle constants). The toughness ( ) estimated this way ranges from 1.0 to 1.9 MPa m and shows a clear dependency to substrate composition: higher values were extracted on oxygen-free fibers. The / ratio, estimated to equal 1.8 and independent to substrate type, is a key parameter that would assist further fractographic investigations.
本文报道了一项旨在评估应力强度因子的碳化硅基长丝的系统断口分析。因此,对总共11种纤维类型(所有三代的原样或氯化的Nicalon®和Tyranno®)进行了反复拉伸测试以生成断口表面。发现拉伸强度与缺陷位置(表面或内部)无关。强度与镜面、雾状或羽状纹外半径之间广为人知的线性平方根关系得到了再次确认。这些测量揭示了Nicalon®纤维上存在一些残余拉应力,然而,由于数据广泛分散,这一说法受到质疑。此外,结果表明表面蚀刻处理并未影响(产生或释放)此类残余应力。因此采用零截距来评估特征应力强度因子(镜面、雾状或羽状纹常数)。由此估算出的韧性()范围为1.0至1.9MPa·m,并且明显依赖于基体成分:在无氧纤维上提取到的值更高。估计等于1.8且与基体类型无关的/比值是一个关键参数,将有助于进一步的断口分析研究。