结构陶瓷氧化反应裂纹愈合动力学研究(Ⅲ)模型验证与修正: Al<SUB>2</SUB>O<SUB>3</SUB>-SiC W陶瓷裂纹愈合动力学研究

无机材料学报, 2006, 21(3): 696-700. doi: 10.3724/SP.J.1077.2006.00696

结构陶瓷氧化反应裂纹愈合动力学研究(Ⅲ)模型验证与修正: Al₂O₃-SiC W陶瓷裂纹愈合动力学研究

吕珺 , 郑治祥 , 吴玉程 , 金志浩

1.1. 合肥工业大学材料学院, 合肥 230009

2. 2. 西安交通大学材料强度国家重点实验室, 西安 710049

2. 2. State Key Laboratory for Mechanical Behvior of Materials, Xi'an Jiaotong University, Xi'an 710049, China

关键词：裂纹愈合 , strength , velocity of healing , oxidiation reaction

Kinetic Research of Oxidation Induced Crack Healing of Engineering Ceramics (Ⅲ) Model Testing and Revising: The Kinetic Research of Al₂O₃-SiC W Composite

Lü Jun , ZHENG Zhi-Xian , WU Yu-Cheng , JIN Zhi-Hao

Keywords： crack healing , 强度 , 愈合速度 , 氧化反应

Al2O3-SiC W 材料通过在高温下发生氧化反应, 生成物所引起的体积膨胀对裂纹处的填充迁移, 使裂纹产生愈合现象. 动力学分析表明: Al₂O₃-SiC W材料裂纹愈合速度为- Cv/t=(2πC²_v0·ΔP+F)/(2πB₀C_v)·1/2·(k/t)^1/2, 强度恢复由下式计算σ_f/σ_f0=[1-(2πC²_v0·ΔP+F)/(πB₀C²_v0)·k^1/2·t^1/2]^-1/4, 与Al₂O₃-TiC P材料相比, 增加了一个填充项F, 从物理意义上分析, F是除裂纹面外对裂纹愈合有利的填充面积当量, 就Al₂O₃-SiC W材料而言, F与裂纹面上晶须桥联及晶须露头面积及裂纹周边反应物能够对裂纹处进行填充的面积有关. 1200℃保温时F值约为9.94\times10^-8m².

Oxidation reaction happened when Al₂O₃-SiC W composite heated at high temperature. The reaction producer moved to the crack area which induced crack healing. The kinetic analysis of crack healing of Al₂O₃-SiC W composite shows that: the velocity of crack healing can be showed as: - Cv/t=(2πC²_v0·ΔP+F)/(2πB₀C_v)·1/2·(k/t)^1/2, and the strength recovery can be expressed by the following formula: σ_f/σ_f0=[1-(2πC²_v0·ΔP+F)/(πB₀C²_v0)·k^1/2·t^1/2]^-1/4. Compared with Al₂O₃-TiC P composite, the filling coefficient F was added. The physical meaning of F coefficient is the area equivalent except the crack area. For Al2O3-SiC W composite, F is related to the whisker bridge, whisker emerge, and the area on which reaction producer can follow and fill in the crack. When heated at 1200℃, F is about 9.94\times10^-8 m².

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材料期刊网

结构陶瓷氧化反应裂纹愈合动力学研究(Ⅲ)模型验证与修正: Al2O3-SiC W陶瓷裂纹愈合动力学研究

Kinetic Research of Oxidation Induced Crack Healing of Engineering Ceramics (Ⅲ) Model Testing and Revising: The Kinetic Research of Al2O3-SiC W Composite

参考文献

结构陶瓷氧化反应裂纹愈合动力学研究(Ⅲ)模型验证与修正: Al₂O₃-SiC W陶瓷裂纹愈合动力学研究

Kinetic Research of Oxidation Induced Crack Healing of Engineering Ceramics (Ⅲ) Model Testing and Revising: The Kinetic Research of Al₂O₃-SiC W Composite