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Three different nitrogen ion doses were implanted into a Ti6Al4V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy (XPS). Nano-indentation tests were carried out on the surface of the Ti6Al4V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6Al4V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6Al4V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6Al4V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.  相似文献
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1INTRODUCTION Theapplicationofsurfaceengineeringtech nologieshaspromotedthedevelopmentofremanu facturing,whichplaysanimportantroleinthe sustainabledevelopmentstrategy.Withanewly developednanomaterialsavailable,nanosurfacetechnologies,especiallynanocomposi…  相似文献
3.
Three different nitrogen ion doses were implanted into a Ti6A14V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy (XPS). Nano-indentation tests were carried out on the surface of the Ti6A14V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6A14V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6A14V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6A14V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.  相似文献
4.
The microstructure and nano-tribological properties of 316 austenitic stainless steel have been investigated by using the in situ nano-mechanical testing system Tribolndenter, in which six different normal forces were chosen to make a scratch and indentation. The results show that the contact depth of the indentation increases with the normal force and material is piled up on the edge of the indentation as plastic distortion. The stable nano-hardness and the reduced modulus of 316 austenitic stainless steel are approximately 6 GPa and 160 GPa, respectively. The friction coefficients of 316 stainless steel with conic-type diamond tip have a typical value of about 0.13, 0.15, 0.17, 0.19, 0.22 and 0.25 when the normal forces are kept at 500 μN, 1000 μN, 1500 μN, 2000 μN, 2500 μN and 3000 μN, revealing an increasing trend with the normal forces. The increase of the friction coefficient in the unloading segment may result from the adhesion force caused by the material piled up.  相似文献
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Nano-SiO2 particles strengthened Ni-based composite coating was designed and prepared on steel substrate. The structures and nanoparticle content of the nano-SiO2/Ni composite coating were determined by SEM, EDS and TEM; and the micro mechanical properties were tested by nano-indentation technique. The results show that 56% of particles in the solution are dispersed in size of less than 100 nm, the content of nanoparticles co-deposited in the coating doubles and structure of the coating is more compact and uniform than that of Ni coating. Nano-SiO2/Ni coating exhibits excellent micro mechanical properties, and the nanohardness and elastic modulus are 7.81 GPa and 198 GPa, respectively, which are attributed to finer crystal strengthening, dispersion strengthening and high-density dislocation strengthening of nano-SiO2 particles to the composite coatings. Foundation item: Project (50235030) supported by the National Natural Science Foundation of China; Project (G1999065009) supported by the National Basic Research Program of China  相似文献
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应用纳米压痕技术实测了水泥粒子的弹性模量,并对试样制备技术进行了研究,分析了合理的样本数量。研究表明:应用酚醛树脂镶嵌水泥粒子后再进行磨光、抛光和超声波清洗等工艺可制得表面光洁度符合纳米硬度仪要求的试样;假定水泥粒子的弹性模量服从正态分布,其样本均值为17.4GPa,具有95%保证概率的置信区间为[14.7GPa,20.1GPa],选取20个测试点即可得到较为可靠的数据。  相似文献
7.
The microstructure and nano-tribological properties of 316 austenitic stainless steel have been investigated by using the in situ nano-mechanical testing system Tribolndenter, in which six different normal forces were chosen to make a scratch and indentation. The results show that the contact depth of the indentation increases with the normal force and material is piled up on the edge of the indentation as plastic distortion. The stable nano-hardness and the reduced modulus of 316 austenitic stainless steel are approximately 6 GPa and 160 GPa, respectively. The friction coefficients of 316 stainless steel with conic-type diamond tip have a typical value of about 0.13, 0.15, 0.17, 0.19, 0.22 and 0.25 when the normal forces are kept at 500 μN, 1000 μN, 1500 μN, 2000 μN, 2500 μN and 3000 μN, revealing an increasing trend with the normal forces. The increase of the friction coefficient in the unloading segment may result from the adhesion force caused by the material piled up.  相似文献
8.
Low dielectric constant materials/Cu interconnects integration technology provides the direction as well as the challenges in the fabrication of integrated circuits(IC) wafers during copper electrochemical-mechanical polishing(ECMP). These challenges arise primarily from the mechanical fragility of such dielectrics, in which the undesirable scratches are prone to produce. To mitigate this problem, a new model is proposed to predict the initiation of scratching based on the mechanical properties of passive layer and copper substrate. In order to deduce the ratio of the passive layer yield strength to the substrate yield strength and the layer thickness, the limit analysis solution of surface scratch under Berkovich indenter is used to analyze the nano-scratch experimental measurements. The modulus of the passive layer can be calculated by the nano-indentation test combined with the FEM simulation. It is found that the film modulus is about 30% of the substrate modulus. Various regimes of scratching are delineated by FEM modeling and the results are verified by experimental data.  相似文献
9.
通过纳米压痕技术对鲍鱼壳横切面及纵切面的弹性模量及硬度进行了测试,并建立有限元模型,通过施加载荷进行了模拟分析。结果表明:鲍鱼壳体横切及纵切方向内层到外层弹性模量及硬度值呈上升趋势。  相似文献
10.
为解决传统检测方法无法直接定量检测非晶体熔石英玻璃表面残余应力的问题,基于脆性固体断裂力学理论,推导残余应力的理论计算公式,提出光学元件抛光加工表面残余应力计算新方法。采用尖锐压头进行纳米印压实验,提取压痕过程中对残余应力敏感的参数,并对实验数据进行线性拟合,确定拟合线的斜率,通过测量残余应力引起其他物理参数的变化计算残余应力。对比分析结果表明,计算得到残余应力值与应力双折射仪检测得到的数据基本吻合,验证了提出残余应力计算方法的正确性。  相似文献
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