Microstructure Analysis And Wear Resistance Research Of TC4 Hot-dipped Al Interface

In recent years,with the vigorous development of my country's aviation industry and high-tech fields,the research of titanium alloys in the manufacturing industry has also received more and more attention from us.It has high density,anti-oxidation,easy rusting,and compatibility with the human body.Many excellent chemical properties have been widely used in aviation,flight,military industry,private operation,medical and other aspects.However,due to the relatively low hardness and insufficient wear resistance of titanium alloys,it still restricts its development prospects,so improving its wear resistance becomes particularly important.This article adopts the hot-dip plating process,using pure aluminum as the coating material to form a layer of titanium aluminum coating on the surface of TC4,and then through diffusion annealing treatment at different temperatures and times,so that the diffusion reaction between the coating and the substrate occurs,using XRD,SEM,EDS and micro-hardness tester,analyze the coating structure after hot-dip aluminum plating and the influence of diffusion annealing parameters on the formed coating structure,conduct mechanism analysis of hot-dip plating and thermal diffusion process,and analyze the mechanism of hot-dip aluminum plating and thermal diffusion process.The problems of coating thickness,time and temperature are analyzed kinetics,and the diffusion kinetic equation is obtained.The MDW-2 pin-disk high-speed reciprocating wear tester is used to explore the influence of various diffusion annealing parameters on the wear resistance of the coating through friction and wear,analyze the microstructure of the wear surface,and select the coating with better friction performance.On this basis,the wear behavior of the titanium-aluminum coating under different sliding conditions was further studied by changing the sliding conditions(load,speed).Draw the following conclusions through experiments:First,after hot-dip aluminum plating at 750°C,scanning electron microscopy shows that the plating layer is divided into three areas,and a layer of Ti Al₃structure is formed between the TC4 and the pure Al layer.With the extension of time,the morphology of Ti Al₃structure did not change significantly,and the thickness did not change much within the range of 5min-15min of hot dipping,about 3-4?m.After 20min of hot dipping,the thickness of the coating doubled to about 6?m.After hot-dip aluminum plating at 850°C,a large number of Ti Al₃masses appeared in the coating structure,and with the extension of time,the Ti Al₃structure continued to grow and become denser.Secondly,after heat treatment at 750?,as time goes by,Ti Al,Ti Al₂,Ti₃Al and other titanium-aluminum compounds appear between the TC4 and Ti Al₃layers,indicating that a diffusion reaction occurs at this time;when the thermal diffusion time is 6h,as the temperature increases Improved,the morphology of the coating did not change significantly,and white Al₂O₃appeared around the Ti Al₃grains at 850°C.Through the relationship between the thickness of the reaction layer and the temperature and time,the kinetic equation of the diffusion process is obtained through the kinetic theory:y(28)0.313exp(-81.6×10³/RT)t ^1/2..Finally,the microhardness test was carried out on the samples after different diffusion annealing.It was found that the samples with a diffusion temperature of 650?were lower than those of 750?and 850?,and the samples with different heat treatment times of 750?and 850?were rubbed.In the wear experiment,the morphology and friction coefficient of the grinding surface were analyzed.It was found that the wear resistance of the sample after diffusion annealing at 850?for 6h was the best.After changing the load and speed,the grinding surface diagram of the sample under different wear parameters was analyzed.