喷射沉积高强耐磨功能梯度铝合金组织演变及性能研究

With the development of technology, Al alloyswith excellent comprehensive performance and precise forming technology are required in aerospace. The graded Alalloys with both highstrength and wear-resistancecan resolve the conflicts between excellent mechanical properties and high wear resistance, and are important candidate materials for the application of aerospace structural parts.It is difficult tocontrol thegraded composition during the preparation process, moreover, the mechanism of the microstructure evolution is not clearin current investigations, which seriously hinder the wide application of the graded material.In this project,the ultra high strength Al-Zn-Mg-Cu alloy and the hypereutectic Al-Si alloyare fabricated together with one-step spray deposition technologyto form composition gradient. The relationships between spray density and gradient distribution are established, in addition, the interaction mechanism and the solidification behavior of the two different kinds of dropletsin graded areas during co-deposition are analysed, furthermore, the microstructure formation and evolution mechanism are clarified. The deformation behavior and the control mechanism of bidirectional convection diffusion are explored, and the relationships between the precipitation, the hard particles and the fracture behavior as well as wear restance will be obtained. The project has an important meaning to understand the composition control and the property adjusting mechanism of the graded alloy, and is benifical to promote the application of Al functional graded materialswith both highstrength and wear-resistance.

随着技术发展，在航空航天领域，对高性能铝合金构件及其精密成形技术提出了较高的要求。高强耐磨铝合金梯度板材可解决优异机械性能与高耐磨性之间的矛盾，是未来航空航天结构件重要的备选材料。目前梯度合金在制备过程中存在成分梯度控制困难、组织演变机理不清晰等问题，严重制约了其广泛应用。本项目拟采用一步法喷射沉积技术，实现超高强Al-Zn-Mg-Cu合金与耐磨过共晶Al-Si合金双金属板材成分梯度与冶金质量的控制，建立喷射密度与梯度分布规律之间的关系；分析异质雾化熔滴梯度区共沉积时相互作用机制与凝固行为，揭示梯度区组织形成及演变机理；探索梯度区合金变形行为及元素双向对流扩散控制机制，阐明析出相和硬质颗粒与断裂行为和耐磨性能之间的关系。研究成果对揭示梯度合金的成分控制和性能调控机理，推进高强耐磨铝合金功能梯度材料的应用具有重要意义。

高强耐磨铝合金梯度板材可解决优异机械性能与高耐磨性之间的矛盾，是未来航空航天结构件重要的备选材料。本项目采用一步法喷射沉积技术，通过设备改造和工艺优化，实现超高强铝合金与Al-Si合金双金属板材成分梯度与冶金质量的控制；通过对梯度材料凝固组织的分析，揭示了异质雾化熔滴梯度区共沉积时相互作用机制与凝固行为和梯度区组织形成及演变机理；在单成分高强铝合金和Al-Si合金变形的基础上，本项目创造性的选择了轧制和准热等静压技术对梯度材料进行变形处理，探索了温度和压力等工艺对梯度板材组织和致密度的影响规律，揭示了梯度区合金变形行为及元素双向对流扩散控制机制。研究成果对揭示梯度合金的成分控制和性能调控机理，推进铝合金功能梯度材料的应用具有重要意义。