Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by...Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.展开更多
Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization an...Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization and tribological behavior of PMMA processed using an excimer laser were investigated in this study by contrasting diferent lubrication conditions and friction cycles. The results show that the roughness of the material surface increases with laser processing, which changes its physical structure. Under lubrication, the laser-treated PMMA exhibits better hydrophilicity, especially during the use of eye drops. No obvious relationship exists between the laser-processing time and friction behavior. However, the laser treatment may contribute to the formation of friction and wear mechanisms of PMMA materials. Laser-treated PMMA in saline solution exhibits better abrasive resistance by showing a lower wear rate than that in eye drops, although it has a higher friction coefcient. In this study, the diferent friction stages in laser-treated PMMA were clarifed under two lubrication conditions. The wear rates of the laser-treated PMMA were found to decrease with the number of cycles, and the friction coefcient has a similar variation tendency. The wear behavior of the laser-treated PMMA is dominated by the main abrasive wear and secondary transferred flm formation. This study provides a theoretical basis for the development and application of ophthalmic biomaterials in complex environments by examining the material surface interface behavior and wear mechanism after laser processing using PMMA as the research matrix.展开更多
The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, ...The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, the FSP was carried out with tool rotational speed of 1600 r/min, tool travel speed of 25 mm/min and tool tilt angle of 3° through only a “single pass”. The optical and scanning electron microscopies, microhardness and reciprocating wear tests were used to characterize the samples. The results showed that the addition of MoS2 lubricant particles to A413/SiCp surface composite leads to the decrease of friction coefficient and mass loss. In fact, the generation of mechanically mixed layer （MML） containing MoS2 lubricant particles in A413/SiCp/MoS2p surface hybrid composite results in the reduction of metal-to-metal contact and subsequently leads to the improvement of tribological behavior.展开更多
High quality Zn base powder with low oxygen content, fine particle size and fine microstructure can be obtained by gas atomization using nitrogen. Cast and sintered Zn 27%Al alloys (ZMJ) were prepared. Tribological be...High quality Zn base powder with low oxygen content, fine particle size and fine microstructure can be obtained by gas atomization using nitrogen. Cast and sintered Zn 27%Al alloys (ZMJ) were prepared. Tribological behaviors of the cast and sintered alloys under lubricated and non lubricated conditions were studied and compared. Worn surfaces and microstructures of these alloys were examined. Results indicate that although the strength of the sintered alloy is considerably less than that of the cast alloy, the sintered alloy has a better wear resistance. The fine microstructure obtained by rapid solidification is beneficial to the wear resisting property. The wear volume of sintered ZMJ is only 36% and 59% of the wear volume that found in cast ZMJ under non lubricated and lubricated conditions, respectively. For lubricated wear test, abrasive wear is the major wear mechanism and for non lubricated wear test, oxidation wear and adhesive wear are the major wear mechanisms.展开更多
目的研究高镍钛基合金(TiNi)的摩擦学性能以提高其使用精度和服役寿命。方法以TiNi为研究对象,结合仿生学方法在TiNi表面设计并制备了鱼鳞状表面织构。随后将复合固体润滑剂Sn AgCu-Al_(2)O_(3)(S-A)均匀填充至织构,使用摩擦磨损测试仪...目的研究高镍钛基合金(TiNi)的摩擦学性能以提高其使用精度和服役寿命。方法以TiNi为研究对象,结合仿生学方法在TiNi表面设计并制备了鱼鳞状表面织构。随后将复合固体润滑剂Sn AgCu-Al_(2)O_(3)(S-A)均匀填充至织构,使用摩擦磨损测试仪对制备的样品进行摩擦实验。最后利用场发射扫描电子显微镜和三维表面形貌仪对磨痕表面进行表征,重点分析表面织构的角度参数对复合材料Sn Ag Cu-Al_(2)O_(3)/TiNi(S-A/TiNi)摩擦学性能的影响。结果与TiNi相比,当表面织构的角度为70°时,S-A/TiNi-70°的平均摩擦因数和磨损率分别降低约81.8%和85.5%,其值分别约为0.1和1.2×10^(-13)m^(3)/(N·m)。结论研究过程中发现,S-A/TiNi-70°试样表现的优异摩擦学性能依赖于S-A固体润滑膜的完整性,摩擦表面形成的固体润滑膜越连续其表面磨损越小。S-A/TiNi-70°试样优异的摩擦学性能主要归因于在表面织构角度为70°时,织构凹槽中的S-A固体润滑剂相较于其他角度更容易流动。这导致织构凹槽中的润滑剂能够大量迁移到摩擦表面形成S-A固体润滑膜,从而减少了摩擦副和基体直接接触。展开更多
基金Project(51371097)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.
基金Supported by the Chengdu Municipal Medical Research Project(Grant Nos.2019005 and 2022014)Sichuan Provincial Cadres Health Research Project(Grant No.ChuanGanYan(2013-104)).
文摘Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization and tribological behavior of PMMA processed using an excimer laser were investigated in this study by contrasting diferent lubrication conditions and friction cycles. The results show that the roughness of the material surface increases with laser processing, which changes its physical structure. Under lubrication, the laser-treated PMMA exhibits better hydrophilicity, especially during the use of eye drops. No obvious relationship exists between the laser-processing time and friction behavior. However, the laser treatment may contribute to the formation of friction and wear mechanisms of PMMA materials. Laser-treated PMMA in saline solution exhibits better abrasive resistance by showing a lower wear rate than that in eye drops, although it has a higher friction coefcient. In this study, the diferent friction stages in laser-treated PMMA were clarifed under two lubrication conditions. The wear rates of the laser-treated PMMA were found to decrease with the number of cycles, and the friction coefcient has a similar variation tendency. The wear behavior of the laser-treated PMMA is dominated by the main abrasive wear and secondary transferred flm formation. This study provides a theoretical basis for the development and application of ophthalmic biomaterials in complex environments by examining the material surface interface behavior and wear mechanism after laser processing using PMMA as the research matrix.
文摘The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, the FSP was carried out with tool rotational speed of 1600 r/min, tool travel speed of 25 mm/min and tool tilt angle of 3° through only a “single pass”. The optical and scanning electron microscopies, microhardness and reciprocating wear tests were used to characterize the samples. The results showed that the addition of MoS2 lubricant particles to A413/SiCp surface composite leads to the decrease of friction coefficient and mass loss. In fact, the generation of mechanically mixed layer （MML） containing MoS2 lubricant particles in A413/SiCp/MoS2p surface hybrid composite results in the reduction of metal-to-metal contact and subsequently leads to the improvement of tribological behavior.
文摘High quality Zn base powder with low oxygen content, fine particle size and fine microstructure can be obtained by gas atomization using nitrogen. Cast and sintered Zn 27%Al alloys (ZMJ) were prepared. Tribological behaviors of the cast and sintered alloys under lubricated and non lubricated conditions were studied and compared. Worn surfaces and microstructures of these alloys were examined. Results indicate that although the strength of the sintered alloy is considerably less than that of the cast alloy, the sintered alloy has a better wear resistance. The fine microstructure obtained by rapid solidification is beneficial to the wear resisting property. The wear volume of sintered ZMJ is only 36% and 59% of the wear volume that found in cast ZMJ under non lubricated and lubricated conditions, respectively. For lubricated wear test, abrasive wear is the major wear mechanism and for non lubricated wear test, oxidation wear and adhesive wear are the major wear mechanisms.
文摘目的研究高镍钛基合金(TiNi)的摩擦学性能以提高其使用精度和服役寿命。方法以TiNi为研究对象,结合仿生学方法在TiNi表面设计并制备了鱼鳞状表面织构。随后将复合固体润滑剂Sn AgCu-Al_(2)O_(3)(S-A)均匀填充至织构,使用摩擦磨损测试仪对制备的样品进行摩擦实验。最后利用场发射扫描电子显微镜和三维表面形貌仪对磨痕表面进行表征,重点分析表面织构的角度参数对复合材料Sn Ag Cu-Al_(2)O_(3)/TiNi(S-A/TiNi)摩擦学性能的影响。结果与TiNi相比,当表面织构的角度为70°时,S-A/TiNi-70°的平均摩擦因数和磨损率分别降低约81.8%和85.5%,其值分别约为0.1和1.2×10^(-13)m^(3)/(N·m)。结论研究过程中发现,S-A/TiNi-70°试样表现的优异摩擦学性能依赖于S-A固体润滑膜的完整性,摩擦表面形成的固体润滑膜越连续其表面磨损越小。S-A/TiNi-70°试样优异的摩擦学性能主要归因于在表面织构角度为70°时,织构凹槽中的S-A固体润滑剂相较于其他角度更容易流动。这导致织构凹槽中的润滑剂能够大量迁移到摩擦表面形成S-A固体润滑膜,从而减少了摩擦副和基体直接接触。
