【作者】 刘莉莉；

【导师】 邓建新；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2006， 博士

【摘要】 本文根据陶瓷喷嘴冲蚀磨损特性和梯度功能材料的优异性能，基于梯度功能的技术思想，首次将梯度功能材料的概念引入陶瓷喷嘴的设计及制造，提出梯度陶瓷喷嘴的设计理论和方法，研制开发出具有高性能、长寿命的SiC／(W，Ti)C梯度陶瓷喷嘴，并探索其冲蚀磨损机理。 对喷嘴内磨料速度场和应力场进行了分析，揭示了喷嘴冲蚀磨损的力学机理。结合陶瓷喷嘴的冲蚀磨损特点和应力状态，提出梯度陶瓷喷嘴的设计理论和方法。建立了梯度陶瓷喷嘴的物理模型、组成分布模型及物性参数模型。 提出了梯度陶瓷喷嘴材料设计目标，通过对梯度陶瓷喷嘴材料的物理化学相容性分析计算，确定了SiC／(W，Ti)C材料体系及其各组分的极限体积含量。建立了梯度陶瓷喷嘴残余应力分析模型，采用热-应力耦合方法深入分析了GN-1单向梯度陶瓷喷嘴和GN-2对称梯度陶瓷喷嘴的残余应力及其分布规律。结果表明：GN-1和GN-2梯度陶瓷喷嘴入口或出口处均产生了残余压应力。通过理论分析初步确定SiC／(W，Ti)C梯度陶瓷喷嘴最佳组成分布指数范围为0.5～1，最佳梯度层厚5mm，各梯度层SiC组分差应小于5Vol.％。 对不同结构的梯度陶瓷喷嘴内的磨料运动及应力分布规律进行了研究。得出梯度陶瓷喷嘴最佳入口锥角为15°～20°，该入口锥角范围的梯度陶瓷喷嘴的磨料出口速度最高，且喷嘴应力最小。 研制成功了多种SiC／(W，Ti)C梯度陶瓷喷嘴材料，试验确定了SiC／(W，Ti)C梯度陶瓷喷嘴材料的最佳热压工艺参数为：烧结温度1900℃，保温时间40min，烧结压力30MPa；最佳组成分布指数范围为0.5～0.8，各梯度层最佳SiC组分差为2Vol.％，试验结果与理论分析结果吻合。 全面系统研究了梯度与非梯度陶瓷喷嘴材料的力学性能，梯度陶瓷喷嘴材料的力学性能随梯度层不同而异，其变化规律为梯度陶瓷喷嘴材料表层的硬度和断更多还原

【Abstract】 The idea of functionally gradient material (FGM) theory was used to design of ceramic nozzle based on the erosion wear behaviors of the ceramic nozzles and on the outstanding properties of FGMs. The purpose is to reduce the tensile stress at the entry region of the nozzle during sand blasting processes. The design theory and methods of gradient ceramic nozzle were proposed. SiC/(W,Ti)C gradient ceramic nozzles with high performance and long life have been successfully developed by hot pressing. The erosion wear mechanisms of these gradient ceramic nozzles were investigated.The velocity of the abrasives particles and the stress inside the ceramic nozzle were analyzed. The mechanics mechanisms of the erosion wear of the ceramic nozzle was presented. The design theory and methods of gradient ceramic nozzle were proposed based on the erosion wear behavior and stress status of the ceramic nozzles. The physical, composition distribution, and property parameter models of gradient ceramic nozzle were established.The aim of the design for gradient ceramic nozzle was proposed. The ultimate content of SiC and (W,Ti)C inside SiC/(W,Ti)C gradient nozzle materials were determined based on the physical and chemical compatibility analysis. Finite element models for residual stress analysis were established, and the residual stress statuses inside GN-1 and GN-2 gradient nozzle were analyzed. Results showed that compressive residual stresses were appeared both at the entry zone and at the exit area of the gradient nozzle. The optimum parameters of the component distribution exponent, the layer thickness, and the volume difference of SiC in various gradient layers of the SiC/(W,Ti)C更多还原