氮化碳基陶瓷刀具材料的制备与力学性能研究

采用热压烧结工艺,以Ti(C, N)为添加相,以Mo、Ni和Co为金属相,成功制备了氮化碳(C₃N₄)基陶瓷刀具材料,测量了其断裂韧度、抗弯强度和维氏硬度,分析了其微观组织。结果表明,在烧结温度为1600℃、保温时间为45 min和烧结压力为32 MPa的工艺条件下,Ti(C, N)质量分数为35%、Ni-Co质量分数为8%的C₃N₄基陶瓷刀具材料力学性能最优。合适的Ti(C, N)含量能细化C₃N₄晶粒、提高烧结密度、改善力学性能,合适的Ni-Co含量能使微观组织细小均匀。     

Postprocessor development for ultrasonic cutting of honeycomb core curved surface with a straight blade

When ultrasonically cutting honeycomb core curved parts, the tool face of the straight blade must be along the curved surface’s tangent direction at all times to ensure high-quality machining of the curved surface. However, given that the straight blade is a nonstandard tool, the existing computer-aided manufacturing technology cannot directly realize the above action requirement. To solve this problem, this paper proposed an algorithm for extracting a straight blade real-time tool face vector from a 5-axis milling automatically programmed tool location file, which can realize the tool location point and tool axis vector conversion from the flat end mill to the straight blade. At the same time, for the multi-solution problem of the rotation axis, the dependent axis rotation minimization algorithm was introduced, and the spindle rotation algorithm was proposed for the tool edge orientation problem when the straight blade is used to machine the curved part. Finally, on the basis of the MATLAB platform, the dependent axis rotation minimization algorithm and spindle rotation algorithm were integrated and compiled, and the straight blade ultrasonic cutting honeycomb core postprocessor was then developed. The model of the machine tool and the definition of the straight blade were conducted in the VERICUT simulation software, and the simulation machining of the equivalent entity of the honeycomb core can then be realized. The correctness of the numerical control program generated by the postprocessor was verified by machining and accuracy testing of the two designed features. Observation and analysis of the simulation and experiment indicate that the tool pose is the same under each working condition, and the workpieces obtained by machining also meet the corresponding accuracy requirements. Therefore, the postprocessor developed in this paper can be well adapted to the honeycomb core ultrasonic cutting machine tool and realize high-quality and high-efficient machining of honeycomb core composites.     

产品方案低碳设计研究综述与展望

温室气体(GHGs)排放是全球气候问题日益严重的重要原因,成为人类社会面临的共同挑战。产品设计阶段对其生命周期的环境产生重要影响,低温室气体排放产品的设计和开发对于缓解气候变化至关重要。聚焦于产品方案低碳设计的“设计-评价-再设计”过程,围绕产品方案的低碳设计信息建模、碳足迹评估、低碳决策优化以及低碳设计工具开发四个方面,分析了其研究的现状与应用场景。针对现有产品方案低碳设计研究存在的设计信息关联难集成、清单数据动态难获取、设计信息海量难优化、设计工具分散难融合等问题,提出了产品方案低碳设计的发展愿景和研究方向：1)复杂映射关联机制下的设计信息集成建模,2)融合设计场景的碳足迹评估策略,3)低碳设计多目标、多阶段智能决策优化方法,以及4)低碳设计集成工具开发。     

机床能量效率测试方法的多场景综合评价研究

机床量大面广,能耗总量巨大,提升机床能量效率已经成为发展绿色制造的重要内容。如何选择合适的机床能效测试方法是支撑机床设计、用户采购、运行优化和节能改造等场景下提升机床能量效率的基础性问题。为此,首先总结和比较了八种能效测试方法的内涵和特点,包括参考样件法、参考过程法、比能法、组件定标法、ISO 14955-3标准、GB/T 40735标准、固有能效潜力评估法和固有曲面法。然后,从五个场景(指导高能效机床优化设计、评选高能效机床制定能效标签等)和七个维度(操作耗时程度、操作难易程度、机床对比适用度等)评价机床能效测试方法。其中,运用层次分析法(AHP法)确定特定场景下七项评价指标的权重因素和各项评价指标下八种能效测试方法权重因素,并通过一致性检验来验证评价结果的有效性和准确性。     

多头小直径深层搅拌桩在水库坝体截渗中的应用与研究

多头小直径深层搅拌桩是利用水泥等材料作为固化剂,通过专用的多头小直径搅拌机械,将地基土和固化剂强制搅拌,固化剂和地基土之间产生一系列物理化学反应后凝结成具有一定厚度、强度和抗渗性能的连续桩体。介绍了该桩在某水库大坝截渗中的应用,指出多头小直径在土石坝、堤防截渗中具有造价低、功效快的特点,具有广泛的推广应用价值。     

High-entropy carbide-based ceramic cutting tools

In this study, a novel high-entropy carbide-based ceramic cutting tool was developed. The cutting performance of three kinds of high-entropy carbide-based ceramic tools with different mechanical properties for the ISO C45E4 steel were evaluated. Although the pure (Ti_0.2Zr_0.2Nb_0.2Ta_0.2Mo_0.2)C_0.8 ceramic cutting tool exhibited the highest hardness of 25.06 ± 0.32 GPa, the cutting performance was poor due to the chipping and catastrophic failure caused by the low toughness (2.25 ± 0.27 MPa m^1/2). The (Ti_0.2Zr_0.2Nb_0.2Ta_0.2Mo_0.2)C_0.8–15 vol% cobalt cutting tool with highest fracture toughness (6.37 ± 0.24 MPa m^1/2) and lowest hardness (17.29 ± 0.79 GPa) showed the medium cutting performance due to the low wear resistance caused by the low hardness. The (Ti_0.2Zr_0.2Nb_0.2Ta_0.2Mo_0.2)C_0.8–7.7 vol% cobalt cutting tool showed the longest effective cutting life of ∼67 min due to the high wear resistance and chipping resistance caused by the high hardness (21.05 ± 0.72 GPa), high toughness (5.35 ± 0.51 MPa m^1/2), and fine grain size (0.60 ± 0.15 μm). The wear mechanisms of the cobalt-containing (Ti_0.2Zr_0.2Nb_0.2Ta_0.2Mo_0.2)C_0.8 ceramic cutting tools included adhesive wear and abrasive wear and oxidative wear. This research indicated that the high-entropy carbide-based ceramics with high hardness and high toughness have potential use in the field of cutting tool application.     

Modeling and Flow Sheet Simulation of Selected Mechanical Recycling Processes for Li-Ion Batteries

To investigate the mechanical processes of Li-ion battery recycling in more detail, models for the different unit processes are to be developed. Here, model approaches for the cutting mill and the zig-zag-sifter are presented. These models are to be used in dynamic flow sheet simulations, with which the individual unit processes as well as the combination to a small process chain were simulated. Thereby, the dynamic interactions between the process steps were investigated, which can be used later for optimization and regulation of the processes. The particle sizes after the cutting mill process as well as the mass flow between the processes influence the separation behavior of the sifter. These changes in the separation function due to an increasing mass flow out of the mill are shown.     

不同药剂处理对早紫葡萄的扦插效应

用IAA 根旺、NAA 生根、生根、IBA 生根等药剂处理早紫葡萄插条的试验,结果表明:IBA 生根在插条根长、根粗、根鲜重、根干重及新梢平均生长量等重要指标上均明显优于其它各处理.因此,建议在生产中推广应用.     

条格织物组织识别中的图像分割方法

针对条格组织的特点，运用K-均值算法对从织物图像中提取的纹理谱统计特征进行分类，提取出条格组织中不同织物组织结构块，从而将这类组织的织物图像分割成一系列简单图像，使织物组织的识别过程大大简化。