结构陶瓷氧化反应裂纹愈合动力学研究 (Ⅱ)模型验证:Al_2O_3-TiC_p结构陶瓷裂纹愈合动力学研究

Kinetic Research of Oxidation Induced Crack Healing of Engineering Ceramics (Ⅱ) Model Testing: The Kinetic Research of Al_2O_3-TiC_p Composite

Al2O3-TiCp材料通过在高温下发生氧化反应,生成物对裂纹处的填充迁移,使裂纹产生愈合现象．加热温度、保温时间、压痕载荷均对愈合效果产生影响．对Al2O3-TiCp材料裂纹愈合动力学研究表明:含裂纹材料强度的恢复符合公式:σf/σf0=[1-2△Pk^(1/2)/B0·t1/2]-1/4,愈合速度为-(?)CV/(?)t=c2V0·△P/B0CV·1/2(k/t)^(1/2),反应速率常数、反应时间、反应所带来的体积增加率,裂纹初始尺寸是影响裂纹愈合的关键因素．对Al2O3-TiCp材料裂纹愈合前后的强度变化分析证明了裂纹愈合模型的正确性．

Oxidation reaction happened when Al2O3-TiCp composite heated at high temperature. The reaction producer moved to the crack area which induced crack healing. The heating temperature, time, and indentation affected the crack healing greatly. The kinetic analysis of crack healing of Al2O3-TiCp composite shows that： the strength recovery can be expressed by the following formula：（σf）/（σf0）=[1-（2Δp√k）/B0·t^1/2]^-1, and the velocity of crack healing can be showed as： -（δCv）/（δt）=（C^2v0·ΔP）/（B0Cv）·1/2√（k/t） Reaction velocity constant, reaction time, the rate of volume increases due to reaction, and original crack size are four key factors of crack healing. The analysis of strength before and after crack healing proves the correctness of the crack-healing model.