Study On Ultrasonic-Laser Hybrid Additive Manufacturing Process And Mechanical Properties Of TiC-enhanced TC4 Coating

As high-end aerospace equipment has higher and higher requirements for ultra-high speed,high agility,and fast response,the high-end components such as impeller blades,exhaust nozzles,engine casings and other corresponding high-end components have improved high temperature resistance,wear resistance,and corrosion resistance.The research and development needs of the company are becoming increasingly urgent.Among them,titanium alloy has excellent properties such as high strength,high toughness,and corrosion resistance.It is widely used in aerospace and other fields.However,with the development of high-end equipment,its lower hardness and poor friction and wear performance cannot adapt to new equipment.The need for development.With the continuous development of laser additive manufacturing technology,the cladding of ceramic-reinforced titanium alloy on the surface of titanium alloy can effectively improve the problems of low hardness and poor wear resistance of titanium alloys.Therefore,ceramic-reinforced titanium alloy coatings are considered to improve the surface hardness of titanium alloys.And effective means of abrasion resistance.However,in the laser additive manufacturing process,problems such as uneven tissue distribution and excessive local stress are prone to occur.The use of external field auxiliary methods such as preheating and slow cooling,magnetic field assistance,and ultrasonic assistance can improve the organization and stress to a certain extent.Improvement,but limited by the form of the energy field and the way of forming,it is difficult for the auxiliary energy field to achieve precise and efficient intervention in the additive manufacturing process.This paper proposes a composite additive manufacturing method of ultrasound and laser,which uses the cavitation,acoustic current,mechanical and thermal effects of ultrasound to intervene the melting behavior of the molten pool in real time,and explores the ultrasonic-laser composite additive manufacturing of TiC-enhanced TC4 coating.The law of organization evolution in the process reveals the relationship between microstructure and mechanical properties.The specific research content and conclusions are as follows:(1)Explore the process parameters of ultrasonic-laser composite additive manufacturing.Design and build an ultrasonic-laser composite additive manufacturing experimental platform,and select appropriate laser parameters and ultrasonic parameter ranges through theoretical analysis and process experiments.Aiming at the ultrasonic power,which is the parameter that best reflects the effect of ultrasound,conduct ultrasonic-laser composite additive manufacturing experiments.(2)Analyze the influence of ultrasonic power on TiC-enhanced TC4 coating.Analyze the macroscopic morphology,including the surface profile and cross-sectional morphology of the composite coating;analyze the microstructure characteristics of the coating,including phase composition,element distribution,and grain morphology.The results show that with the increase of ultrasonic power,the amount of unmelted TiC in the composite coating decreases,the content of primary TiC increases and the size decreases,the uniformity of the structure distribution increases,and the stress concentration phenomenon decreases.(3)Carry out experiments on the mechanical properties of TiC reinforced TC4 composite coating.Mainly include micro-hardness and friction and wear properties.The study found that with the increase of ultrasonic power,the average microhardness of the composite coating increased significantly.When the ultrasonic power was 1800 W,the average microhardness of the composite coating reached a maximum of 656.70 HV_0.2,which was compared with TC4matrix.An increase of 83.21%,which is an increase of 26.44%compared to the absence of ultrasound.At the same time,with the increase of ultrasonic power,the average friction coefficient of the composite coating gradually increases,and the wear mechanism of the composite coating gradually transitions from abrasive wear to adhesive wear.