超声对TC4表面金刚石复合涂层组织的影响研究

Study on the Influence of Ultrasonic Enhancement on the Microstructure of Diamond Composite Coating on TC4 Surface

为提升钛合金表面的耐磨性,采用超声辅助气保护钎焊技术,在TC_(4)钛合金表面制备了金刚石复合钎涂层,以探究超声对涂层微观组织的影响,并揭示其细化晶粒的机理。通过在AlSi钎料中加入一定比例金刚石粉末和CuTi合金粉,并施加超声波作用,制备了不同工艺参数下的金刚石复合钎涂层。研究结果表明,钎涂层中Cu、Al反应产物的先后生成顺序理论上应依次为Cu9Al_(4)、CuAl_(2)和CuAl;Ti与Al、C三种元素反应,可能形成的化合物分别为TiC和TiAl_(3);超声辅助可以有效促进金刚石颗粒在钎涂层中的均匀分布,并加速钎涂层中的Ti、Al、Cu原子间的相互扩散,在750℃保温90 s,Ti(Cu,Al)_(2)便可在钎涂层组织内出现;钎涂基体组织中存在大量团聚的未长大的Ti(Al_(1-x)Si_(x))_(3),钎涂层组织晶粒发生明显细化,实现了CuAl2相在钎涂层组织中的弥散分布。

To enhance the wear resistance of titanium alloy surfaces,ultrasonic-assisted gas shielded brazing technology was employed to prepare a diamond composite brazing coating on the TC4 titanium alloy surface.This was done to investigate the impact of ultrasound on the microstructure of the coating and to reveal its mechanism for refining grains.By adding a certain proportion of diamond powder and CuTi alloy powder to the AlSi brazing filler metal and applying ultrasonic waves,diamond composite brazing coatings were prepared under different process parameters.The research results show that the order of formation of Cu and Al reaction products in the brazing coating should theoretically be Cu_9Al_4,CuAl_2,and CuAl;Ti reacts with Al and C,and the possible compounds formed are TiC and TiAl_3.Ultrasonic assistance can effectively promote the uniform distribution of diamond particles in the brazing coating and accelerate the mutual diffusion of Ti,Al,and Cu atoms in the brazing coating.At 750°C with a holding time of 90 seconds,Ti(Cu,Al)_(2) can appear within the brazing coating structure.There are many aggregated ungrown Ti(Al_(1-x)Si_x)_(3) in the brazing substrate structure,and the grain size of the brazing coating structure is significantly refined,achieving a dispersed distribution of the CuAl_(2) phase in the brazing coating structure.