Forming Process And Device Of Laser Cladding&Laminated Object Deposition Of Silicon Carbide Fiber Reinforced Titanium-based Composite

As an advanced material in the aerospace field,SiCf/TC4 composite is widely used and has always been the focus of research at home and abroad.Compared with the traditional manufacturing method of SiCf/TC4 composite,the laser cladding &laminated deposition technology has the advantages of short preparation cycle and low cost,and has broad application fields and prospects.First of all,in view of the high rigidity and easy breaking of SiC fiber,a fiber winding and storage program was developed.Fibers were inserted into side-by-side plastic capillaries with an outer diameter of 0.5 mm and an inner diameter of 0.3 mm,making the fiber easy to wind and stretch.The fiber spacing is reduced to 0.5 mm.The wire drawing device was optimized,and a number of neat small grooves were processed in the groove of the wire drawing base.The precise combination of grooves ensures smooth fiber laying.The winding device is matched with the drawing device to ensure the neat laying of fibers with uniform gaps.Secondly,the fiber forming angle,fiber laying density and fiber laying crown were studied.When the angle between the advance direction of the laser cladding head and the fiber was 0°(parallel),a single fiber was subjected to continuous thermal load,and the fiber was easy to burn;when the angle between the advance direction of the laser cladding head and the fiber was 90°(vertical),a single fiber was subjected to cyclic thermal load,and was not easy to burn;The optimal fiber density was 75%;the fiber will have a pavement crown under the action of thermal stress,which will cause a different defocus amount and affect the forming quality.Thirdly,the process parameters were optimized for the three factors of laser power,scanning speed,and powder feeding amount that have the greatest influence on composite forming.The influence law of laser power and powder feeding amount on the experimental results was linear,and not change with the change of other factors.The forming quality decreases with the increase of laser power,and increase with the increase of powder feeding.The influence of scanning speed on formability was affected by laser power and powder feeding rate.There was an interaction between the three factors.Using orthogonal experiments with interaction,the optimal process parameters are obtained as laser power 250 W,powder feeding rate 2.5 g/min,and scanning speed 6 mm/s.Finally,the observation of the structure of the SiCf/TC4 composite and the measurement of the interface reaction layer were carried out.The presence of SiCf/TC4 composite fiber changed the organizational morphology.The matrix away from the fiber was equiaxed grain,and the crystal grains near the fiber became finer,and some were dendritic;the elements in the interface reaction layer were Ti,Si,C,V,the phases in the sample included Ti C,Ti5Si3,?-TI,?-Ti,Al Ti3,SiC,Ti C was the main component of interfacial reaction layer.