The low temperature solid deposition characteristics of cold spraying technology are conducive to the remanufacturing/repair of oxidation sensitive titanium alloy in the atmosphere. Ti6Al4V alloy deposits prepared by cold spray (CS) usually show porous microstructure due to insufficient plastic deformation of Ti6Al4V alloy particles. The interfacial bonding and the microstructural evolution mechanisms of Ti6Al4V particles during cold spray are still unclear. In this study, the Ti6Al4V deposits were prepared by cold spray with nitrogen as process gas at a temperature of 800 °C and a pressure of 4 MPa. The micron CT results show that the porosity is 8.25%. The deformation ultrafine grain zone and un-deformation martensitic laths zone at the bonding interface between Ti6Al4V particles were observed. The EBSD results show that the grain orientation signal was only detected at the edge of the particles deformation area and the 23% of grain sizes detected by EBSD are less than 500 nm, which indicates that the nanocrystallization induced by dynamic recrystallization occurs at the inter-particle boundaries between cold-sprayed Ti6Al4V particles. The TEM and SADPs demonstrate a gradient structure consisting of equiaxed nanograins zone, crushing dendrites transition zone and original martensitic laths zone from the interface to the core of particles.

冷喷涂技术的低温固相沉积特性有利于大气中氧化敏感钛合金的再制造/修复。由于 Ti6Al4V 合金颗粒的塑性变形不足，冷喷涂 (CS) 制备的 Ti6Al4V 合金沉积物通常呈现多孔微观结构。Ti6Al4V 颗粒在冷喷涂过程中的界面结合和微观结构演变机制尚不清楚。在这项研究中，Ti6Al4V 沉积物是通过用氮气作为工艺气体在 800 °C 的温度和 4 MPa 的压力下冷喷涂制备的。微米CT结果显示孔隙率为8.25%。在Ti6Al4V颗粒结合界面观察到变形超细晶粒区和未变形马氏体板条区。EBSD 结果表明，晶粒取向信号仅在颗粒变形区域的边缘处检测到，EBSD 检测到的 23% 的晶粒尺寸小于 500 nm，这表明动态再结晶诱导的纳米化发生在颗粒间。冷喷涂 Ti6Al4V 颗粒之间的颗粒边界。TEM 和 SADP 显示出由等轴纳米晶粒区、破碎枝晶过渡区和从界面到颗粒核心的原始马氏体板条区组成的梯度结构。