Titanium honeycomb components which suffered damage during service are usually in urgent need of timely repair. The currently prevailing repair method is melt welding, which often causes serious metallurgical defects. The relatively low operating temperature of cold spray is considered to be able to prevent the oxidation of metal particles in comparison. In our work, TC4 titanium alloy coatings were deposited by cold spray on surfaces of AA2024 aluminum alloy and TC4 titanium alloy substrates, respectively. And subsequently SEM, XRD, Vickers hardness test and three point bending test were carried out for the resultant coatings, in order to evaluate the influence of substrates' hardness and thermal characteristics on coatings' microstructures and mechanical properties. Results showed that, compared with AA2024 substrate, TC4 substrate, which owns higher hardness, lower heat capacity and lower thermal conductivity, has a less fluctuating interface with the sprayed TC4 coating, a higher particle surface temperature, and promotes the metallurgical bonding owing to the formation of a ～ 5 μm layer of adiabatic shear band among particles' contact interfaces. This contributes to the lower porosity and more satisfactory deposition effect, and in consequence, higher micro-hardness, better bending property, smooth fractured surface characterized by brittle fracture with no phase change happened. Our research confirmed the feasibility of repairing titanium alloy components by applying cold spray technique.%钛合金蜂窝壁板在服役中受损急需修复, 现有的修复手段以熔化焊为主, 易导致严重冶金缺陷, 而冷喷涂的相对低温可使此问题得以避免.采用冷喷涂在AA2024铝合金和TC4钛合金基体上制备了TC4钛合金涂层, 借助SEM、XRD、维氏硬度试验、三点弯曲试验研究了基体硬度和热特性对涂层微观组织和力学性能的影响.结果表明, 与AA2024基体相比, 硬度较高、比热容和导热系数较低的TC4基体与TC4涂层间界面的起伏较小, 颗粒表面温度较高, 颗粒接触面形成宽度约为5μm的绝热剪切带, 促进了冶金结合.因此, TC4基体表面冷喷涂涂层的孔隙率较低, 沉积特性较好;涂层平均微观硬度较高, 弯曲性能较好, 断口平整, 呈脆性断裂, 未发生相变.本实验证实了通过喷涂修复钛合金构件的可行性.
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