静态SHS陶瓷内衬复合喷嘴的抗热疲劳性能研究

Study of Resistance to Thermal Fatigue of Ceramic-lined Nozzles Prepared by Static Self-propagating High-temperature Synthesis

陶瓷内衬复合管的热疲劳损伤机理不同于整体陶瓷材料,本文采用静态自蔓延法制备出陶瓷内衬复合喷嘴并进行了热疲劳性能试验,分析了影响陶瓷内衬复合管热疲劳性能的影响因素,试验表明复合管切割产生的缺口或裂纹是造成热疲劳损伤的重要原因,在热疲劳循环过程中形成的交变压应力的作用下,切割处的缺口或裂纹向里沿轴向扩展,造成热疲劳损伤和破坏。陶瓷层中的金属颗粒与陶瓷晶体之间的弱结合界面为裂纹扩展通道和内部起裂源,喷嘴的变口径处对热疲劳影响不大,通过改进生产工艺及配方,改善了内衬陶瓷层的抗热疲劳性能。

The mechanics of the thermal fatigue damage of the ceramic-lined pipes is different from that of the homogeneous ceramic.The ceramic-lined nozzles have been prepared by the static self-propagating high-temperature synthesis(SHS) process,and the thermal fatigue test is carried out.This paper studies the influencing factor of the thermal fatigue of these ceramic-lined nozzles.The result shows that the nicks and cracks caused by cutting have the major adverse effect on the performance.The nicks and cracks extend into the nozzle under the influence of the cyclic compressive stress,and then damage the ceramic.The weak interface between the metal grains and ceramic grains is the extending channel and the inside origins.The cyclic thermal fatigue has the less influence on change over portion.This study improves the resistance to thermal fatigue through techniques and changing reaction system.