高频窄脉冲电解加工技术能有效提高加工精度和表面质量，在镍基高温合金等难加工金属材料的精密制造方面有着广泛的应用。然而，对于微观组织极不均匀的激光定向能量沉积构件，其加工质量尚不清晰，尤其是采用无水电解液时。以激光定向能量沉积Inconel 718合金为研究对象，采用频率为30~100 kHz、占空比为30%~80%的高频窄脉冲电流以及饱和NaCl乙二醇电解液进行射流电解加工实验。结果表明：沉积态Inconel 718合金组织由γ基体相、Nb偏析区与枝晶间相（主要为γ/Laves共晶相）组成；在10.50 A/cm²的电流密度下，加工区表面粗糙度随脉冲频率的增加而增大，且脉冲频率为30 kHz时表面粗糙度最小（R_a=1.562 μm），加工精度最高；表面粗糙度随占空比的增加先减小后增大，占空比为50%时表面粗糙度最小，占空比为60%时加工精度最高；而在直流模式下，表面粗糙度随电流密度的增大而降低，且电流密度为10.50 A/cm²时，表面质量最优（R_a=0.526 μm），这是由于高电流密度更容易诱导表面“过饱和盐膜”的形成，从而有效抑制选择性溶解，降低表面粗糙度。但在加工精度方面，高频窄脉冲电流模式的加工定域性较好。最后，基于“盐膜”理论和双电层模型，揭示了高频窄脉冲电流模式下沉积态Inconel 718合金的微区阳极溶解机理，为提高激光增材制造镍基高温合金射流电解加工表面质量提供了理论支撑和实验依据。

为了验证激光清洗飞机蒙皮表面漆层的可行性，阐明漆层清除对基材表面完整性的影响，采用脉冲光纤激光器在12.89~25.48 J/cm²能量密度下对2024铝合金飞机蒙皮开展了除漆实验，研究了除漆效果、基材表面形貌、粗糙度、显微硬度及微观组织特征的变化规律，利用Ansys Workbench软件模拟分析了温度场分布对除漆效果和基材表面完整性的影响。结果表明，随着能量密度的增大，残漆率降低，基材表面粗糙度（S_a）和峰谷高度差（PVHD）增大，显微硬度小幅提升，同时表面晶粒细化，位错密度增大，强化相σ（Al₅Cu₆Mg₂）析出，当能量密度大于22.90 J/cm²时，漆层彻底清除。在22.90 J/cm²的能量密度下，漆层与基材交界处的温度为415.46 ℃，低于基材的初始熔化阈值，基材表面未发生明显的塑性变形，PVHD为8.28 μm，显微硬度相较于原始试样提高了2.8%，获得了良好的表面完整性。研究结果为提升激光除漆技术在航空工程领域中的应用可靠性与安全性提供了参考。

Carbon fiber reinforced plastic (CFRP) has been applied in aeronautics, aerospace, automotive and medical industries due to its superior mechanical properties. However, due to its difficult-to-cut characteristic, various damages in twist drilling and chip removal clog in core drilling could happen, inevitably reducing hole quality and hole-manufacturing efficiency. This paper proposes the wave-motion milling (WMM) method for CFRP hole-manufacturing to improve hole quality. This paper presents a motion path model based on the kinematics of the WMM method. The wave-motion cutting mode in WMM was analyzed first. Then, comparison experiments on WMM and conventional helical milling (CHM) of CFRP were carried out under dry conditions. The results showed that the hole surface quality of the CFRP significantly improved with a decrease of 18.1%–36% of Ra value in WMM compared to CHM. WMM exerted a significantly weaker thrust force than that of CHM with a reduction of 12.0%–24.9% and 3%–7.7% for different axial feed per tooth and tangential feed per tooth, respectively. Meanwhile, the hole exit damages significantly decreased in WMM. The average tear length at the hole exit in WMM was reduced by 3.5%–29.5% and 35.5%–44.7% at different axial feed per tooth and tangential feed per tooth, respectively. Moreover, WMM significantly alleviated tool wear. The experimental results suggest that WMM is an effective and promising strategy for CFRP hole-manufacturing.

为了研究激光冲击处理对GH3039高温合金表面完整性的影响，对GH3039高温合金试样进行了不同次数的激光冲击。采用表面轮廓仪、显微硬度计及X射线衍射仪等表征了激光冲击前后GH3039高温合金的表面粗糙度、显微硬度、残余应力、微观结构及物相组成。结果表明：与母材相比，在激光一次、二次和三次冲击后，试样的表面粗糙度平均值分别增加了28.5%、54.1%和109.1%，表面显微硬度分别增加了21.4%、26.5%和28.6%，试样的近表层平均晶粒尺寸分别减小了54.5%、57.1%和59.3%；激光冲击处理将试样表面的残余应力由拉应力（75 MPa）转变为压应力（一次冲击后为-275 MPa、二次冲击后为-302.4 MPa和三次冲击后为-335 MPa）；激光冲击试样的变形层深度由1.2 mm左右（一次冲击）增加到1.5 mm左右（三次冲击）；随着冲击次数的增加，衍射峰的半峰全宽明显增大，这归因于晶粒细化和微观应变的增加。

Particulate-reinforced metal matrix composites (PRMMCs) are difficult to machine due to the inclusion of hard, brittle reinforcing particles. Existing experimental investigations rarely reveal the complex material removal mechanisms (MRMs) involved in the machining of PRMMCs. This paper develops a three-dimensional (3D) microstructure-based model for investigating the MRM and surface integrity of machined PRMMCs. To accurately mimic the actual microstructure of a PRMMC, polyhedrons were randomly distributed inside the matrix to represent irregular SiC particles. Particle fracture and matrix deformation and failure were taken into account. For the model’s capability comparison, a two-dimensional (2D) analysis was also conducted. Relevant cutting experiments showed that the established 3D model accurately predicted the material removal, chip morphology, machined surface finish, and cutting forces. It was found that the matrix-particle-tool interactions led to particle fractures, mainly in the primary shear and secondary deformation zones along the cutting path and beneath the machined surface. Particle fracture and dilodegment greatly influences the quality of a machined surface. It was also found that although a 2D model can reflect certain material removal features, its ability to predict microstructural variation is limited.

激光增材制造具有快速、柔性和绿色制造等技术优势, 但增材制造过程中高的温度梯度变化和不均匀相变所致的拉应力, 易导致零件的变形和力学性能不足。本文针对激光增材GH1131高温合金薄壁件进行激光冲击强化处理, 以激光能量、冲击次数为变化量, 分析了激光冲击强化前后薄壁试样件的表面变形、表面粗糙度、表面残余应力、表面硬度。结果表明, 激光冲击强化后, 相对于激光冲击强化方向, 薄壁件呈现凸面变形, 并且变形量、表面粗糙度增加, 分别增加了48.87 μm、0.43 μm; 随着激光能量的增加, 试样件表面残余应力和表面显微硬度先增加后减小, 相比初始件分别增加了352 MPa、48 HV; 随着冲击次数的增加, 薄壁件呈现凸面变形, 并且变形量、表面粗糙度增加, 分别增加了45.78 μm、0.65 μm; 试样件表面残余应力和表面显微硬度均增加, 相比初始件分别增加了572 MPa、198.2 HV,但增加量有所减少。

Anisotropy is one central influencing factor on achievable ultimate machined surface integrity of metallic materials. Specifically, grain boundary has a strong impact on the deformation behaviour of polycrystalline materials and correlated material removal at the microscale. In the present work, we perform molecular dynamics simulations and experiments to elucidate the underlying grain boundaryassociated mechanisms and their correlations with machining results of a bi-crystal Cu under nanocutting using a Berkovich tool. Specifically, crystallographic orientations of simulated bi-crystal Cu with a misorientation angle of 44.1° are derived from electron backscatter diffraction characterization of utilized polycrystalline copper specimen. Simulation results reveal that blocking of dislocation motion at grain boundaries, absorption of dislocations by grain boundaries and dislocation nucleation from grain boundaries are operating deformation modes in nanocutting of the bi-crystal Cu. Furthermore, heterogeneous grain boundary-associated mechanisms in neighbouring grains lead to strong anisotropic machining behaviour in the vicinity of the grain boundary. Simulated machined surface morphology and machining force evolution in the vicinity of grain boundary qualitatively agree well with experimental results. It is also found that the geometry of Berkovich tool has a strong impact on grain boundary-associated mechanisms and resultant ploughing-induced surface pile-up phenomenon.

增材制造具有产品开发快速性, 能够直接生产出具有复杂几何形状的金属零件, 同时显著提高材料的利用率、降低成本。增材制造零件在疲劳等关键性能上与锻件仍然存在一定的差距, 需要探寻有效的后处理方法。采用激光喷丸强化增材制造TC4钛合金, 研究增材制造TC4钛合金表面完整性改善效果, 并与同牌号常规锻造钛合金进行强化效果对比。结果表明, 激光喷丸对于两种材料表面粗糙度影响微弱。在硬度方面, 增材制造TC4的表面显微硬度从348 HV增加到367 HV, 影响层深度达0.75 mm, 而常规锻造TC4表面显微硬度从315 HV提高到362 HV, 影响层深度大于1 mm; 在残余应力方面, 激光喷丸在增材制造TC4表面所引入的残余压应力最大值约为400 MPa, 受影响的区域深度约为0.75 mm, 而常规锻造TC4表面所引入的残余压应力最大值约为600 MPa, 受影响区域深度大于1 mm。此外, 利用阿基米德法测量出增材制造TC4的致密度为98.46%, 经过一次激光喷丸处理后提高到98.92%。与锻造TC4相比, 增材制造TC4组织相对疏松, 可能是导致激光喷丸所引入残余应力幅值较小, 影响层深度较浅的原因。

为了研究中高温条件下激光冲击处理对Ti-6Al-4V钛合金的表面完整性的影响, 采用高功率、短脉冲Nd∶YAG激光器对Ti-6Al-4V钛合金表面进行激光冲击, 并将冲击后的钛合金试样分别置于400℃,500℃,550℃和600℃的温度下进行保温处理。从表面形貌、表面粗糙度、表面残余应力等方面分析了中高温条件下激光冲击处理对Ti-6Al-4V钛合金的表面完整性的影响。结果表明, 激光冲击处理增大了Ti-6Al-4V钛合金的表面粗糙度, 且热处理温度越高, Ti-6Al-4V钛合金的表面粗糙度越大; 激光冲击处理显著提高了Ti-6Al-4V钛合金材料的表面残余压应力, 随着温度的升高, 残余压应力值降低。研究结果对了解和掌握Ti-6Al-4V钛合金的使用性能是有帮助的。