Study on selective laser melting of Al-Mg-Mn alloy under PLC control and its microstructure and properties
The selective laser melting forming system based on PLC control was used for rapid forming of Al-Mg-Mn alloy.The effects of laser scanning speed on the density,microstructure,phase and hardness of the formed parts were studied,and the effects of aging temperature and time on the compression properties of the formed parts were investigated.The results show that with the laser scanning speed increasing from 700 mm/s to 1 300 mm/s,the po-rosity of the formed sample increases and the relative density decreases gradually under the condition of other pro-cess parameters unchanged.With the increase of laser scanning speed,the weld pool parallel to the deposition di-rection gradually increases,and the fusion line becomes thinner.Multilayer deposition channels with cross distribu-tion can be seen perpendicular to the deposition direction,but when the laser scanning speed is 1300mm/s,the weld channel contour is relatively vague;At the same laser scanning speed,the hardness of the plane parallel to the depo-sition direction is higher than that of the plane perpendicular to the deposition direction.With the increase of laser scanning speed,the microhardness of XZ plane and XY plane first increases and then decreases,and the maximum hardness is obtained when the laser scanning speed is 900mm/s;With the increase of aging temperature or the ex-tension of aging time,the microhardness,yield strength and compressive strength of the selective laser melting forming sample first increase and then decrease,and the maximum value is obtained when the aging temperature is 300 ℃ and the aging time is 6 h,which is mainly related to the precipitation strengthening effect of Al3(Sc,Zr)phase in the alloy at this time.
HSS and tool steelspowder metallurgyforming technologymicrostructureapplication
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