Tribological issues during quick plastic forming

Quick plastic forming (QPF) was developed as a high-volume, hot blow forming process for automobile components, enabling larger volume applications than traditional superplastic forming (SPF). One critical aspect of the process is the tribological interaction between the forming tool and the aluminum blank, as this impacts formability, surface quality, and tool durability. While QPF has been successfully implemented for automobile components, many opportunities exist for improving the tribological condition during the process, including the die coating or treatment, the lubricant, and the fundamental understanding of aluminum/iron adhesion under QPF conditions (450 °C). This work reviews key tribological issues affecting QPF and identifies areas where additional research is required. This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium was organized by Daniel G. Sanders, The Boeing Company.     

MoS2含量对Ni基固体润滑涂层性能的影响

采用超音速火焰(HVOF)喷涂的方法在45钢表面制备四种含有MoS2的镍基固体润滑涂层,并研究了MoS2含量对涂层组织和性能的影响.结果表明,MoS2作为一种软质润滑相存在涂层中,能显著降低涂层的摩擦系数和磨损率;随着MoS2含量的增加,涂层中的润滑相和孔隙均增加,而显微硬度和结合强度却呈明显下降趋势.当MoS2含量为6.0%时,涂层的磨损率为0.38×10-3mg·s-1,耐磨性最优.     

提高自动轧管机顶头寿命的理论分析

主要介绍提高自动轧管机顶头寿命的理论分析及模拟计算，顶头温度场分布等。     

动静压轴承特性分析与设计

本文在文献的基础上,对动静压轴承的润滑特性规律及其设计进行了较深入的研究。提出了液体润滑工况区域的概念及划分方法;分析了主要设计参数对轴承特性的影响以及改进动静压轴承特性的措施,为这类轴承的设计开发提供了理论依据。     

摩擦状态转化图及其应用研究

本文对金属滑动摩擦副的润滑和失效性能进行了研究，对常用的五种由国产材料组成的摩擦副在混合润滑工况下的性能作了大量试验，分别绘制了摩擦状态转化图，确定了它们的P－V工作区域，为摩擦学设计提供了依据。     

钛合金表面耐磨润滑微弧氧化膜的研究进展

综述了钛合金微弧氧化膜的摩擦学性能研究以及提高膜层耐磨性能和润滑性能所采用的方法,旨在对改善钛合金微弧氧化膜摩擦学性能的研究现状有一个系统全面的认识,并在此基础上展望了未来钛合金微弧氧化膜摩擦学研究的发展趋势和方向。     

油溶性离子液体作为润滑油添加剂的摩擦学性能研究

为解决离子液体在基础油中溶解性差、不宜用作润滑添加剂的问题,通过分子设计制备了极性较小的十六烷基三辛基季膦磷酸二异辛酯盐和十六烷基三辛基季胺多库酯钠盐2种油溶性离子液体,其在碳氢润滑油聚ɑ烯烃(PAO10)中均具有较好的溶解性。采用铜片腐蚀试验考察了2种离子液体的腐蚀性;通过Optimol SRV-IV往复振动摩擦磨损试验机测试了2种离子液体作为PAO10基础油添加剂的摩擦学性能,通过多功能X射线光电子能谱仪(XPS)和原位接触电阻(ECR)表征推导了离子液体添加剂在PAO基础油中的润滑机理。结果表明:2种离子液体作为PAO10的添加剂无腐蚀,完全符合对润滑添加剂的要求。2种离子液体添加剂比空白基础油和传统工业添加剂ZDDP均具有更好的减摩抗磨性能。2种离子液体添加剂会在摩擦副表面形成有效的吸附膜和发生复杂的摩擦化学反应,因而使离子液体具有优异的减摩抗磨性能。     

Stochastic multiscale analysis in hydrodynamic lubrication

A stochastic multiscale analysis framework is developed for hydrodynamic lubrication problems with random surface roughness. The approach is based on a multi‐resolution computational strategy wherein the deterministic solution of the multiscale problem for each random surface realization is achieved through a coarse‐scale analysis with a local upscaling that is achieved through homogenization theory. The stochastic nature of this solution because of the underlying randomness is then characterized through local and global quantities of interest, accompanied by a detailed discussion regarding suitable choices of the numerical parameters in order to achieve a desired stochastic predictive capability while ensuring numerical efficiency. Finally, models of the stochastic interface response are constructed, and their performance is demonstrated for representative problem settings. Overall, the developed approach offers a computational framework, which can essentially predict the significant influence of interface heterogeneity in the absence of a strict scale separation. Copyright © 2017 John Wiley & Sons, Ltd.     

少层石墨烯负载纳米SiO2复合材料对水润滑性能的影响

采用液相超声直接剥离法制备了少层石墨烯负载纳米SiO₂复合材料,采用TEM对其形貌进行了表征,利用多功能往复摩擦磨损试验仪考察了少层石墨烯负载纳米SiO₂复合材料对水润滑性能的影响。通过SEM、XPS分别分析了磨损表面的形貌、元素组成及典型元素的化学状态,初步探讨了石墨烯负载纳米SiO₂复合材料在水中的润滑机理。结果表明:纳米SiO₂均匀分布于少层石墨烯片层表面和层间;其作为水润滑添加剂具有良好的减摩抗磨性能,这主要是由于石墨烯负载纳米SiO₂复合材料在磨损表面形成的摩擦化学反应膜与纳米SiO₂的自修复效应发生协同作用,抑制了Fe的氧化,并填补和修复了磨损表面,使磨痕表面的摩擦磨损减轻。     

齿面凹坑参数对面齿轮等温弹流润滑的影响

根据微分几何基本理论求出面齿轮曲率半径,由齿面相对运动求得面齿轮传动过程中卷吸速度,建立面齿轮等温弹流润滑模型,通过FORTRAN语言编程计算出齿面油膜厚度,分析凹坑直径和深度对油膜膜厚的影响,并通过实验验证理论计算的准确性。研究结果表明:齿轮从啮入到啮出过程中,油膜厚度沿啮合轨迹逐渐增大;当齿面凹坑直径在50~200μm时有增加油膜厚度的作用,其中凹坑直径为100μm时效果最优;当齿面凹坑深度在5~20μm时均有增加油膜厚度的效果,存在最优深度为10μm。