孔用衬套冷挤压的强化机理与疲劳寿命研究进展

以强化后孔结构为研究对象，分析了冷挤压相关技术的研究现状，综述了衬套冷挤压技术的工艺过程及系统组成，分别从应力分布和微观组织演化的角度，对强化作用机理进行了系统分析和总结，详细介绍了孔用衬套冷挤压强化工艺条件对疲劳寿命的影响，归纳总结了孔结构冷挤压技术中疲劳断口分析和寿命预测的研究结果。研究表明，冷挤压强化后孔壁周围的残余应力分布和微观组织有所改善，通过引入残余应力抵消部分外部载荷冲击。同时，有效抑制位错萌生、增值和滑移的有益位错胞形成，阻止了晶粒的滑动，不仅降低了裂纹的扩展速率，而且提高了孔结构抗塑性变形能力。冷挤压强化工艺参数的优化对疲劳寿命有着重要的影响。分析了断口形貌和建立了对应工艺参数的数学模型，可以为疲劳寿命的精准预测提供理论依据。最后，结合实际生产工艺的技术需求，展望了衬套冷挤压强化技术在未来研究中需要解决的关键问题和发展趋势。

Research Progress of Strengthening Mechanism and Fatigue Life in Cold Extrusion of Bushing for Hole

Fastening hole connector is an important basic component in the aviation field, and its stress concentration has always been the focus of academia and industry. Therefore, improving the fatigue strength of the hole-structure is quite essential for enhancing the performance of the aircraft and prolonging its life. The use of cold extrusion technology for hole bushings to strengthen the hole-structure has the advantages of large extrusion volume, high precision and excellent strengthening effect. In recent years, it has been widely used in the anti-fatigue manufacturing and maintenance of aircraft mechanical components. At present, it is widely accepted that the strengthening mechanism of hole bushing cold extrusion technology mainly includes macro/micro aspects. Through extrusion strengthening, effective residual stress was introduced to the hole-structure and the microstructure around the hole wall was improved. Thereby, the fatigue resistance of the hole-structure was enhanced and the service life of the aircraft was improved simultaneously.