钛合金人工关节曲面局部覆盖约束式磨粒流湍流精密加工新方法

人工关节曲面的光滑度对其功能和使用寿命有着至关重要的影响。针对钛合金人工关节曲面的加工难题，提出了一种局部覆盖约束式磨粒流湍流精密加工新方法。通过人工关节曲面的仿形建立局部覆盖曲面约束构件，构建磨粒流受控流道，被加工曲面成为流道壁面的一部分，使磨粒流进入湍流充分发展状态，通过磨粒的无序运动实现表面的微切削，达到镜面级表面粗糙度及高表面质量要求。项目以流体力学和液-固两相流为理论基础，数值模拟磨粒流流场的动态特性，研究局部覆盖曲面约束式微通道的湍流流场形成机制、条件和调控方法，揭示钛合金在湍流形态下的磨粒流作用下的材料去除机理。采用粒子图像测速（PIV）技术观测流场形态，综合纳米压痕、扫描电镜等方法测试分析已加工表面质量，进行工艺参数优化，建立人工关节曲面加工的理论与技术体系，为人工关节的精密加工提供拥有自主知识产权的装备及技术，具有较好的科学研究价值和实际应用前景。

The smoothness of artificial joint curved surface has a critical influence on its function and working life. Aiming at the processing problems for the curved surface of titanium alloy artificial joints, a partial coverage constraint style abrasive flow turbulence precision machining method is proposed for titanium alloy artificial joint. The partial covering surface constraint component is established by profiling of the artificial joint surface, and the controlled flow channel of abrasive flow is built. The processing surface is a part of the flow channel wall, making abrasive flow into the turbulent fully developed state. The micro-cutting of the processing surface is realized by the disorderly movement of the abrasive to reach the mirror level surface roughness. Based on the theoretical basis of fluid dynamics and liquid - solid two-phase flow, the dynamic characteristics of abrasive flow field is simulated, and the turbulent flow field formation mechanism, conditions and control methods of partial coverage constraint micro-channel are researched. The material removal mechanism of titanium is exposited under the action of the abrasive stream in the turbulent form. The Particle Image Velocimetry (PIV) is used to observe the flow field morphology. The machined surface quality is tested by nanoindentation, scanning electron microscopy and etc. The process parameters optimization is fulfilled. The theories and techniques system are established for the artificial joint curved surface machining. It will provide technology and finishing equipment for the artificial joint precision machining with independent intellectual property rights. The project has good scientific value and practical application prospects.