高强度Ti5553合金等径弯角挤压的制备及其冲蚀磨损性能研究

Titanium alloy has a poor property of erosion wear, which is one of the important reasons with materials damage or equipment failure, which also greatly limits its performance and potential application. So the erosion wear of titanium alloy has been focused on in the world. Strength and toughness are considered as major factors which can resist erosion wear. Microstructure and parameter adjustment are an important way which makes an alloy to obtain various strength, performance and plastic matching. In the project, high strength Ti5553 alloy is studied. Submicro-grain Ti5553 alloy with high strength and high toughness is prepared by equal channel angular pressing. Microstructure, strength, toughness and other mechanical properties are studied. It is reviewed that high temperature ECAP technology on the influence and mechanism of its erosion wear properties. The interaction relations between microstructure and high temperature recovery crystallization and the impact mechanism on its erosion wear properties are analyzed by using re-crystallization thermodynamic and kinetic theory. The content of the project not only contributes to enrich the theory of tribology, but also to explore a new way for the application of high strength Ti5553 alloy.

钛合金的冲蚀磨损性能差，是引起材料破坏或设备失效的一个重要原因，极大限制了其性能和应用潜力的发挥。因此，钛合金的冲蚀磨损问题在国际上一直是研究的热点。强度和韧性是决定材料抗冲蚀磨损性能的主要因素。显微组织和参数的调整是使一种合金获得各种不同强度、使用性能和塑性匹配的重要途径。本项目以高强Ti5553合金为研究对象，应用ECAP工艺研制微米晶Ti5553高强韧合金，研究微米晶Ti5553合金中显微组织与强韧性等力学性能以及高温ECAP工艺对其冲蚀磨损性能的影响规律与机制；运用再结晶热力学与动力学理论研究显微组织与高温恢复再结晶二者之间的相互制约关系及其对冲蚀磨损性能的作用机制。本项目研究内容不仅有助于丰富摩擦学理论，而且为高强Ti5553合金的实际应用探索一条新途径。

钛合金自20世纪50年代问世以来，受到材料界广泛重视，被认为是21世纪最具有发展前途的新型结构材料之一。然而，钛合金本身质地较软，冲蚀磨损性能较差。流动体系中的冲蚀磨损广泛存在于航天航空、舰艇、机械、能源及军工等许多领域，是引起材料破坏或设备失效的一个重要原因。机械加工热处理是解决材料冲蚀磨损问题的主要途径之一。β型和近β型钛合金因具有良好的冷、热加工性能，易锻造，可轧制、焊接，可通过机械加工热处理获得较高的机械性能、良好的环境抗力及较高的强度，正日益成为世界各国争相研究的高强钛合金系列之一。.本项目以近β型Ti5553合金为研究对象，运用新型的纯剪切变形热加工工艺——等径转角挤压工艺制备了微米晶Ti5553合金块体材料，确定了等径转角挤压工艺制备微米晶Ti5553合金的关键因素；研究了ECAP工艺对Ti5553合金力学性能和冲蚀磨损性能的影响，探讨了Ti5553合金的冲蚀磨损特征，阐明了高温ECAP工艺对Ti5553合金冲蚀磨损性能影响的作用机理。本项目通过ECAP工艺实现了晶粒细化和各性能之间的相互匹配，提高了Ti5553合金的抗裂纹扩展能力和冲蚀磨损能力，丰富了摩擦学理论，为Ti5553合金的实际应用提供了重要的理论依据。