Threshold Stress for Crack‐Healing of Si3N4/SiC and Resultant Cyclic Fatigue Strength at the Healing Temperature
Threshold Stress for Crack‐Healing of Si3N4/SiC and Resultant Cyclic Fatigue Strength at the Healing Temperature
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DOI：
10.1111/j.1551-2916.2005.00106.x
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发表时间：
2005-03
影响因子：
3.9
通讯作者：
Koji Takahashi;K. Ando;H. Murase;S. Nakayama;S. Saito
中科院分区：
文献类型：
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作者：
Koji Takahashi;K. Ando;H. Murase;S. Nakayama;S. Saito
采用热压法制备了Si 3 N4/SiC复合陶瓷，研究了应力作用下裂纹的愈合行为。在每个试样上制作表面长度为100 μm的半椭圆形表面裂纹。对预裂纹试件在循环应力和恒定弯曲应力作用下进行裂纹愈合，研究其弯曲强度和循环疲劳强度。在1000°和1200°C的愈合温度下研究了裂纹愈合的阈值应力。还研究了裂纹愈合试样在900°和1000°C愈合温度下的循环疲劳强度。主要结论如下：（1）裂纹愈合的门槛应力为300 MPa，是裂纹愈合后试样抗弯强度的75%;（2）在900°和1000°C的裂纹愈合温度下，裂纹愈合后试样具有较高的循环疲劳强度。
Si3N4/SiC composite ceramics were hot-pressed in order to investigate the crack-healing behavior under stress. Semi-elliptical surface cracks of 100 μm in surface length were made on each specimen. The pre-cracked specimens were crack-healed under cyclic or constant bending stress, and the resultant bending strength and cyclic fatigue strength were studied. The threshold stress for crack-healing was investigated at healing temperatures of 1000° and 1200°C. The cyclic fatigue strengths of crack-healed specimens were also investigated at healing temperatures of 900° and 1000°C. The main conclusions are as follows: (1) The threshold cyclic and constant stresses for crack-healing, below which pre-cracked specimens recovered their bending strength, were 300 MPa, which was 75% of the bending strength of the pre-cracked specimens and (2) the crack-healed specimens exhibited quite high cyclic fatigue strength at crack-healing temperatures of 900° and 1000°C.