Study On The Process Characteristics Of Wire Based Laser Additive Manufacturong

Laser additive manufacturing technology(LAM)(also known as "3D printing")using material layer by layer accumulation method of manufacturing solid parts,which has the potential to create any complex shape homogeneous or heterogeneous functional structure with a single device,and it was widely used in the aerospace,biological engineering,military and other fields.In this paper,a laser mental-wire additive manufacturing technology based on wire material is proposed.The process of laser mental-wire additive manufacturing for 5356 aluminum alloy wire and Ti-6Al-4V titanium alloy wire is studied under vacuum,Meanwhile,Infrared(IR)thermography is used to monitor the process in real-time.The effects of process parameters on the quality of cladding chanel surface,microstructure and properties were analyzed,and also the characteristics of temperature field were researched.Otherwise,based on the single-later single-bead experiment,the multi-layer single-bead laser mental-wire additive manufacturing experiment on titanium alloy was carried out,and the forming quality,microstructure and microdomain composition of thin-walled components under different lap rate η were studied,and temperature accumulation during the forming process of thin-walled components were analyzed.And provide technical and theoretical support for the optimizated parameters of thin-walled components.As to single-layer single-bead laser mental-wire additive manufacturing experiment on aluminum alloy,the results indicated that the forming qualiy is better with lower scanning speed and wire feeding speed.Otherwise,through the IR thermography,as scanning speed increases,the cooling rate also increases,while as wire feeding speed increases,it dicreases.IR thermography can be used to predict the width of cladding channel and the size of grain.And found that it is in good agreement with that in experimental measurement.And then proved the IR thermal feedback data is more reliability.As to single-layer single-bead laser mental-wire additive manufacturing experiment on titanium alloy,comparative analysis shown that the forming quality of titanium alloy wire is better than that of aluminum alloy wire.The orthogonal test about laser power,scanning speed and wire feeding speed was designed,and the optimized parameters were as follows: laser power is 180 W,scanning speed is 6mm/s,wire feeding speed is 6mm/s.Based on single-layer single-bead experiment of titanium alloy,the experiment of thin-walled components was carried out.The results shown that when the overlap rate η = 36%,the forming quality of thin-walled component is better.The analysis of microstructure indicated that: the top of thin-walled component is fine and long needle-like martensite ?’;the middle is short rod-shaped α and β,and the grains are fine,the distribution are organizational,namely basketweave Widmanst?tten alpha;the bottom is the short and thick α and the original β phase.According to the comparation of properties,microhardness in the top and region of the thin-walled component is higher than that of other areas.In the scanning direction,tensile strength is higher than that in the forming direction,while,the plasticity is lower.Otherwise,it is found that the thermal accumulation effect of temperature in the thin-walled component can be obtained more intuitively by the IR thermography.The data illustrated that the cooling rate decreases with the layers increase.Therefore,the experiment of this paper has laid a foundation for laser mental-wire additive manufacturing under vacuum.And the real-time on-line monitoring of IR can realize the monitoring temperature of heating and cooling process,then provided theoretical support for parameters optimization In addition,the using of IR by monitoring the cooling rate to control the process,and then achieved the regulation of microstructure,and it has significance influence on process parameters optimization of real-time during laser mental-wire additive manufacturing.