宽带光束与同轴粉末流耦合规律及熔覆层成形特征

发布时间：2018-04-03 03:39

本文选题：激光熔覆　切入点：平顶激光束　出处：《中国表面工程》2017年05期

【摘要】：利用高功率宽带平顶光束进行熔覆试验,采用高速摄像机和图像处理软件,建立了宽带光束-同轴粉末流耦合模型,研究了不同送粉器粉盘转速和载气流量下激光束与同轴粉末流的耦合特性和规律,并通过金相显微镜和体视显微镜分析不同光粉耦合形态下熔覆涂层的成形特征与规律,构建了光粉耦合特性与熔覆层成形的关系。结果表明:在载气流量不变的条件下,随粉盘转速增加,粉末流与激光束的耦合位置逐渐由宽带光束内变成宽带光束外,粉末流汇聚点焦距增大,汇聚直径先增大后保持不变;在基体处的区域由焦柱粉流区变为环状粉流区,熔覆层宽度略减小,高度和接触角增大,粉末利用率先增大后减小,稀释率减小。在粉盘转速不变的条件下,随载气流量增加,粉末流与激光束的耦合形态不变,粉末流位于宽带光束外,粉末流汇聚点焦距先增大后减小,汇聚直径先增大后保持不变;在基体处的区域由环状粉流区变为焦柱粉流区,熔覆层宽度先增大后减小,高度和接触角先增大后保持不变,粉末利用率先增大后减小,稀释率减小。当粉盘转速为1.2 r/min,载气流量为4 L/min时,能够获得较好的成形质量。
[Abstract]:A wideband beam-coaxial powder flow coupling model was established by using high-speed camera and image processing software.The coupling characteristics and rules of laser beam and coaxial powder flow under different powder plate speed and carrier gas flow rate were studied, and the forming characteristics and rules of cladding coating under different photo-powder coupling morphology were analyzed by metallographic microscope and stereoscopic microscope.The relationship between optical powder coupling and cladding forming was established.The results show that the coupling position of powder flow and laser beam changes gradually from inside the broadband beam to outside, the focal length of the convergent point of the powder flow increases, and the convergent diameter first increases and then remains unchanged with the increase of the carrier gas flow rate.In the region of the matrix, the powder flow zone of the coke column is changed into the annular powder flow zone, the width of the cladding layer decreases slightly, the height and the contact angle increase, the powder utilization increases first and then decreases, and the dilution rate decreases.Under the condition of constant rotating speed of powder disk, the coupling morphology of powder flow and laser beam is invariant with the increase of carrier gas flow rate. The powder flow is located outside the broadband beam. The focal length of the convergent point of powder flow first increases and then decreases, and the convergent diameter first increases and then remains unchanged.In the region of matrix from annular powder flow zone to focal column powder flow zone, the width of cladding layer first increases and then decreases, the height and contact angle first increase and then remain unchanged, the powder utilization increases first and then decreases, and the dilution rate decreases.When the rotating speed of the powder disk is 1.2 r / min and the flow rate of carrier gas is 4 L/min, the better forming quality can be obtained.
【作者单位】：温州大学浙江省激光加工机器人重点实验室;温州市质量技术监督检测院;
【基金】：国家自然科学基金(51605338) 浙江省博士后科研择优资助项目(156184) 浙江省教育厅资助项目(Y201430593)~~
【分类号】：TG174.4

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