摘要
通过原位化学包覆工艺制备的可加工Al2O3/BN纳米复合材料,其抗热震性能明显优于Al2O3基体材料.热震温差ΔTc从195℃提高到约395℃,抗热震损伤性能也得到相应的改善.高的抗热震断裂性能源于材料的弹性模量的大幅下降和保持了较高的强度;而优良的抗热震损伤性能则是因为具有弱层间结合的BN易产生大量的微裂纹,屏蔽了热弹性应变能,从而使热震裂纹趋向于准静态扩张.
Thermal shock resistance of machinable Al2O3/BN nanocomposites, fabricated via chemical coating process and subsequently hot -pressing, was investigated. The experimental results revealed both thermal fracture resistance and thermal damage resistance of the nanocomposites were obviously improved in comparison with Al2O3 monolith. A temperature difference （ AT. ） increase of about 100 percent, from 195℃ for Al2O3 monolith to 395℃ for the nanocomposites was found in this work, which was mainly attributed to the low Young＇ s modulus and relatively high strength due to the soft h -BN addition and its homogegeous distributions with super fine grain size. Layer - structured h - BN can help to relax stress and absorb energy through microcracking, and then prevent sudden decrease of the residual strength after thermal shock.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2007年第2期248-250,共3页
Materials Science and Technology
基金
国家自然科学基金资助项目(50072017)
北京市优秀人才培养专项资助项目(20041D0501509)
