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1、第32卷第4期中国激光Vol.32,No.42005年4月CHINESEJOURNALOFLASERSApril,2005文章编号:025827025(2005)0420562205同轴送粉激光成形中粉末与激光的相互作用1122席明哲,虞钢,张永忠,石力开1中国科学院力学研究所,北京1000802北京有色金属研究总院复合材料中心,北京100088摘要详细介绍了同轴送粉激光成形过程中,金属粉末与激光束相互作用时间的计算方法。在ANSYS软件平台上,建立了金属粉末穿越激光束过程中粉末温度场的计算模型。系统计算了不同颗粒大小316L不锈钢粉末与不同功率激光束相互作用后的温度。在此基础上,计算了金属粉
2、末与激光束的能量交换及金属粉末落入激光熔池后与激光熔池的能量交换。计算结果表明,在激光束直径为3mm条件下,316L不锈钢粉末穿过功率大于1000W的激光束后,所有尺寸金属粉末均被熔化,即金属粉末以液态进入激光熔池。通过金属粉末与激光束及激光熔池的能量交换计算,可知在激光成形中,约有5%的激光能量用于加热和熔化粉末,而大约95%的激光能量用于激光熔池的形成及由于热传导造成的热量损失。关键词激光技术;激光直接成形;金属粉末;能量交换;有限元法;温度场中图分类号TN249文献标识码AInteractionoftheLaserBeamandtheMetalPowderConveyedbyCoaxia
3、lPowderFeeder1122XIMing2zhe,YUGang,ZHANGYong-zhong,SHELi-kai1InstituteofMechanics,TheChineseAcademyofSciences,Beijing100080,China2ResearchCenterforNonferrousMatelsComposites,GeneralResearchInstituteforNonferrousMetals,Beijing100088,ChinaAbstractAmethodtocalculatetheinteractiontimebetweenmetalpowdera
4、ndlaserbeamduringlaserdirectformingwiththemetalpowderconveyedbycoaxialpowderfeederisintroducedindetailed.Afiniteelementmethod(FEM)modelbasedonANSYSsoftwareisestablishedtocalculatethetemperatureofthemetalpowderwhileitcrossesthroughthelaserbeam.Underdifferentlaserpowercondition,afterinteractionwithlas
5、erbeam,thetemperatureofthe316Lstainlesssteel(SS)powderofdifferentsizeiscalculated.Thusthelaserenergyabsorbedfromlaserbeambymetalpowdersiscalculated.After316LSSpowdershaveenteredlasermoltenpool,theenergyexchangebetweenlasermoltenpooland316LSSpowdersisalsocalculated.Thecalculatedresultsshowthatall316L
6、SSpowdersaremeltedaftertheyhavecrossedthroughthelaserbeamwithpowerlargerthan1000W.Itistosaythatthe316Lstainlesssteelpowdersareturnedfromsolidintoliquidbeforetheyreachthesurfaceoflasermoltenpool.Thecalculatedresultsalsoshowthatduringlaserdirectforming,approximately5%oflaserenergyisusedtoheatandmeltme
7、talpowdersand95%oflaserenergyisusedtoformlasermoltenpoolandtocompensatetheheatlossduetothermalconduction.Keywordslasertechnique;laserdirectforming;metalpowder;energyexchange;finiteelementmethod;temper