Research on Continuous/Pulse Laser Cladding Superalloy K403 钟如涛 熊征
摘 要
针对飞机叶片激光熔覆的特殊要求,利用横流CO2激光器及加工系统,系统地研究了连续/脉冲CO2激光对K403材料熔覆质量的影响规律。结果表明,相同线能量下脉冲激光熔覆与连续激光熔覆相比,外表光滑、平整、熔覆层与基体的界面结合完整,稀释率低20%,熔覆层硬度高5%,热影响区小50%。脉冲激光熔覆K403材料减少了合金元素的聚集和低熔点共晶组织的形成,缩小了“液态薄膜”的产生范围,同时由于基材变形小,降低了冷却凝固过程中的拉应力,较高的过热度使熔覆层液体与基体液体充分混合,降低了基体的脆性,解决了K403材料连续CO2激光熔覆易产生裂纹的问题。
标 签 激光技术 激光熔覆 连续/脉冲激光 K403材料 laser technique lasercladding continuous/pulse laser K403 material
Abstract
Aiming at the special requirement of laser cladding on aereoengine blade, the influences of continuous/pulse beam on cladding performance for K403 substrate was studied experimentally on a transverse CO2 laser and its processing system,compared with continuous laser beam,by using pulse laser beam,the hardness of cladding layer increased for about 5%,while the duty rate and area of heat-affected zone decreased for about 20% and about 50%,respectively. Cladding with pulse laser beam could weaken the gathering of alloy elements and the formation of low melting eutectic structure,resulting in the absence of liquid state membrane on grain boundary. In addition,the tension stress in solidification is greatly reduced during pulse laser cladding due to the less deform of substrate,and a higher degree of superheat induced fully mixing of the melting pool and decreased the brittleness of substrate,so,the heat cracking behavior of K403 substrate under continuous laser beam cladding was avoided under pulse laser beam cladding.
Erosive Wear Resistance Behavior of Laser Cladding Al2O3+13%TiO2 Coating Prepared by Plasma Spraying on Titanium Alloy Surface
高雪松 黄因慧 田宗军 刘志东 沈理达 王东生
激光修复机摘 要
以钛合金为基体,Al2O3+13%TiO2(质量分数)为喷涂粉末,运用激光熔覆等离子体喷涂工艺制备陶瓷涂层。采用喷砂式冲蚀试验机进行冲蚀磨损实验。采用三维视屏显微镜研究涂层磨损表面形貌。并利用X射线衍射仪(XRD)对激光熔覆前后涂层的成分进行了分析。结果表明,激光熔覆过程中,陶瓷涂层成分均一致密化,使涂层的抗冲蚀性能提高;结果也同时阐述了随着冲蚀角的增加,激光熔覆陶瓷涂层冲蚀量超过等离子体涂层的原因,提出了陶瓷涂层冲蚀涂层的经验关联式。
标 签 激光技术 钛合金 激光熔覆 等离子体喷涂 Al2O3+13%TiO2 冲蚀磨损 laser technique titanium alloy laser cladding plasma spray Al2O3+13%TiO2 erosive wear
A ceramic coating on a matrix of titanium alloy was prepared with powdered Al2O3+13%TiO2 (mass fraction) by using laser cladding of plasma-sprayed process. Erosive wear resistance of the ceramic coating was tested with an erosion-blasting machine. The worn surface of coating was observed through a three-dimensional video microscope. The coating’s composition before and after laser cladding was analyzed by X-ray diffraction (XRD). The results show that during the course of laser cladding,the composition of ceramic coating is distributed uniformly and densely,therefore enhancing the coating’s anti-erosion performance. The experimental findings explain why with erosion angle increasing,there is more weight-loss in laser cladding coating than in plasma-sprayed coating. The empirical equations of the erosion weight-loss were also obtained.
基于STL模型的五轴激光切割轨迹生成
Generation of 5-Axis Laser Cutting Path Based on STL Model
朱虎 扶建辉
摘 要
提出一种基于切口特征自动识别的五轴三维激光切割轨迹自动生成方法。采用STL模型,通过切口特征自动识别实现了切口特征的自动选取,并通过对切口边环的偏置实现了激光束半径补偿;利用切口边环的离散点确定了激光束入射点位置,并利用激光束入射点所在三角面片的法向量确定了激光头姿态;算法应用实例表明,该方法能够实现切口特征的自动选取和激光束半径补偿,并能保证激光头始终与工件表面保持垂直,软件系统运行稳定可靠。
标签 激光技术 激光切割 轨迹 STL文件
laser technique laser cutting path STL file
A method for automatically generation of 5-axis 3D laser cutting path was proposed based on automatic recognition of incision features. Automatic selection of incision features was realized through automatic recognition of incision features using STL (stereo lithography) model. The laser beam radius compensation was done by offsetting of the ed
ge loop of incision. The positions of laser beam focal points were decided according the discrete points on the edge loop of incision. The laser head posture was determined using the normal vector of triangle face on which the laser beam focal points was located. The case studies indicate that the method can automatically select incision features and carry out laser beam radius compensation automatically,at the same time can ensure the laser head perpendicular to the surface of workpiece all the time. The operation of software system is stable and reliable.
激光烧结WC颗粒增强镍基合金块体成形实验研究
Experimental Research on Formation of Laser Sintering WC Particles Reinforced Ni-Base Alloy Bulk
介绍了直接激光金属烧结(DMLS)成形WC颗粒增强镍基高温合金的基本原理,采用扫描电子显微镜(SEM),X射线衍射仪(XRD)和显微硬度计对烧结块体的微观形貌和成分进行了分析,研究了不同的工艺参数(激光功率、扫描速度)对烧结区的微观形貌、成分和微观硬度的影响。结果表明,在激光功率为900 W,扫描速度为0.7 m/min时,激光烧结性能较好,烧结致密度
高,WC颗粒熔化为枝晶均匀地分散在基体中,增强颗粒能被固液界面捕捉,使WC颗粒能够很好地分散在基体里,提高烧结块体的性能。通过试验得到了一组优化的工艺参数,并由此烧结出结构致密、硬度较高的金属块体。
标 签 激光技术 激光烧结 WC颗粒 镍基合金 成形 laser technique laser sintering WC particles Ni-base alloy formation
Theory of preparation of sub-micro WC particles reinforced Ni-base super alloy matrix composite using direct metal laser sintering (DMLS) is introduced. The effects of processing parameters ,such as laser power,scanning speed on the microstructures,composition and microhardness of the laser sintered samples were characterized by X-ray diffraction (XRD),scanning electron microscope (SEM ) and microhardness tester. The result shows that the examples prepared by laser sintering have better performance and higher density under the laser power of 900 W,scanning speed of 0.7 m/min,for WC particles melt as dendrites disperse evenly in the matrix and can be captured by solid-liquid interface. The compact metal bulks with high hardness are fabricated successfully by DMLS with optimized processing parameters.
激光烧蚀铁靶的等离子体特性
Plasma Characteristics of Metal Fe Ablated by Pulsed Laser
高勋 郭凯敏 宋晓伟 谭勇 厉宝增 李海军 林景全
摘 要
利用YAG脉冲激光烧蚀(PLA)空气环境中的Fe靶,观测激光诱导等离子体发射光谱。采用不同脉冲能量,对380.0-420.0 nm的等离子体发射光谱进行了时间、空间分辨研究。在局部热力学平衡条件下,根据所测谱线的相对强度,利用Saha方程得到等离子体电子温度约为104 K。根据测得谱线的半峰全宽(FWHM),推得等离子体电子密度约为1017 cm-3。给出了靶面附近等离子体电子温度、电子密度的时间及空间演化规律。
标 签 激光技术 激光烧蚀 等离子体发射光谱 电子温度 电子密度 laser technique laser ablation plasma emission spectroscopy electron temperature electron density
Laser-induced plasma spectroscopy of Fe target in air is investigated. Time and space-re
solved spectra in the wavelength range of 380.0-420.0 nm are measured at different laser pulse energies. Under the model of local thermodynamic equilibrium,electronic temperature of Fe plasma is deduced to be around 104 K with assistance of Saha equation. Electron density of Fe plasma is obtained to be about 1017 cm-3 by use of the full-width at half maximum (FWHM) of Fe spectral lines. Spatio-temporal evolution,electron temperature as well as electron density near the target are presented.
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