| In this paper, through the injection of SiC-316L mixed particles, on the surface of magnesium alloy AZ31B laser melt injection process, using the Gambit modeling software to establish the laser melt injection analysis model, using Fluent to Sic-316L mixed particles of magnesium matrix composite coating by means of temperature field and flow field numerical simulation analysis, and through the discrete phase model simulations of particles in melt pool distribution, get the conclusion as follows:(1) On the laser fuse note temperature field simulation, through the different laser power and laser scanning speed on different simulation comparison, choose the optimal a set of process parameter the laser power3000w and the scanning speed is5mm/s; Temperature field is elliptical distribution; and Similar to the comet shape.(2) According to the molten pool of surface and cross section of the topography, we can see that the pool of penetration, the fusion width and fuse long size, and laser power is proportional to size, and laser scanning speed is inversely proportional, Through the molten pool center temperature curve, can estimate in the process parameter the laser power1800w, the scanning speed is5mm/s, the craft parameter the laser power2500w, the scanning speed is5mm/s and process parameter the laser power3000w, the scanning speed is5mm/s of the molten pool existence time is respectively0.8s,1.1s and1.5s.(3) For different process parameters of laser molten note molten pool of flow field motion law is simulated. With the increase of laser power, molten pool the highest velocity and the minimum velocity increases with increasing together, and the highest velocity and minimum velocity difference also will increase. The reason that has this kind of situation because laser power increases, the matrix unit area absorption of heat will increase, the weld pool temperature gradients within will also increase, surface tension increases, thus the liquid flow rate increases, also led to the highest liquid velocity and minimum velocity difference increase; Molten pool the highest velocity and the minimum velocity and the difference and laser scanning speed is inversely proportional,(4) General surface tension temperature coefficient is negative value, namely liquid metal surface tension with the rise of temperature decline, and therefore:laser fuse note molten pool surface tension distribution from the molten pool center around to increase gradually; but as a result of molten pool temperature distribution is not symmetrical, molten pool front end temperature gradually reduce, molten pool end temperature rise gradually; according to the high temperature area surface tension is small, so the molten pool formed two sizes whirlpool, large left, right small.(5) SiC-316L hybrid particles can inject molten pool condition analysis. Based on the formula (6-1) To calculate the SiC-316L hybrid particles injected into the molten pool in which the minimum speed of vr for0.94m/s; through calculating powder carrier gas velocity of53.7～70.7m/s, and through type (6-8) particles in molten pool are calculated speed vp of3.26～5.84m/s; liquid metal viscosity and temperature process function; by type (6-19) to calculate the constant C value was1.654cP.(6) Injecting a mixed particulate SiC-316L at different angles in the end of the liquid metal bath to calculate the trajectory of mixed particles of SiC-316L, respectively, to vr=3.12m/s and VR=5.24m/s the speed of the mixed particles of SiC-316L Getinto the liquid metal bath, the analog to calculate the trajectories of the particles within the bath. Finally can know, in the case of the same incident angle, the greater the initial speed, the longer the particle trajectories; injection trajectory of an angle of50°than30°angle of the steep, but the particles are more likely to sink to the bottom, the better. |
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