Design On The Equipment And Research On The Process Parameters Of Laser Cladding & Laminated Object Depositon Of SiC Fiber Reinforced Titanium Matrix Composites

SiC_f/Ti-based composites are popular aerospace materials due to their excellent properties such as high specific strength,high specific stiffness,high temperature resistance,and fatigue resistance.The use of SiC_f/Ti-based composite materials for aircraft skins can improve the high-temperature resistance of the aircraft surface,and increase the upper limit of the aircraft’s flying speed,and reduce the weight of the aircraft without reducing the strength.The traditional method of manufacturing the material has the disadvantages of high cost,waste of time,special tooling needed and mold required.Laser Cladding&Laminated Depositon(LCLD)is used to produce SiC fiber-reinforced titanium-based composites with short manufacturing cycles,low manufacturing costs,no special tools and molds,and complex parts.Research work is carried out in three aspects:control system,equipment and three-dimensional forming technology.Firstly,according to the requirements of the SiC_f/Ti-based by Laser Cladding&Laminated Depositon,the SiC_f/Ti composite Laser Cladding&Laminated Depositon equipment was designed.The design includes a wire drawing equipment,a four-dimensional motion platform,and forming room design.The wire drawing equipment was designed to realize the accurate placement of SiC fibers on the forming plane.The four-dimensional motion platform with the forming size of 300mm×300 mm×20 mm and the forming accuracy of±0.2 mm was designed.The forming chamber was designed and it realized the titanium alloy powder feeding,the protective gas feeding,the laser input,the cooling water feeding and other input functions.It also can provide the required argon environment function for SiCf/Ti-based composite LCLD forming.Then,the control card and driver was used to build a motion system that controls the above-mentioned design equipment,that is the on-off control of the laser,powder feeder,carrier gas feeder,protective gas feeder,wire clamps and four linear motion platforms.The control software was developed by MFC to support the equipment,realize the communication between PC and control card,read and display CLI data,debug motion,manage the process parameter,control I/O switch,generate the forming code,and monitor forming Process and so on.Finally,SiCf/Ti-based composite material process experiments,which mainly included one-dimensional forming,two-dimensional forming,and three-dimensional preliminary forming,were conducted by the developed equipment and control system.A one-dimensional forming and fiber laying study was carried out.The results showed that the designed wire drawing equipment can accurately place the fiber on the forming plane;the larger the powder feeding rate,the higher the fiber retention;the high laser power and low scanning speed can cause fiber damage;the effect of laser power on fiber damage is greater,and the critical scaning rate of fiber burnout gradually increased with the increasing laser power.When the laser power is 360 W,the critical scan rate of fiber burnout is 6 mm/s.A two-dimensional forming study was conducted,and the results showed that remelting can reduce inter-channel defects;the interface thickness decreases with increasing remelting scanning speed;the content of Ti and Si elements in the interface reaction layer changed linearly,and the trend of change is opposite.Matrix to fiber,TiC,Ti3SiC2,and SiC phases may exist at the fiber-matrix interface.A three-dimensional preliminary forming study was conducted,and the results showed that the fiber retention was good after remelting,and there were basically no defects.Subsequent forming had no effect on the fiber retention of the bottom layer.