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 distributio...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 ni-trogen 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 di-mension 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 de-crease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.展开更多
Using ANSYS software, we developed a modeling program for several kinds of wire ropes with metal cores and built a geometric model for the 6×19 IWS wire rope. Through proper grid partitioning, a finite element mo...Using ANSYS software, we developed a modeling program for several kinds of wire ropes with metal cores and built a geometric model for the 6×19 IWS wire rope. Through proper grid partitioning, a finite element model for calculating the deforma-tion of wire rope was obtained. Completely constraining one end of the wire rope and applying an axial force to the other end, we established the boundary conditions for solving the model. In addition, we numerically simulated the stress and deformation of the wire, obtaining the deformation distribution of each wire within the wire rope under different laying directions. At the end, a tensile test of the 6×19 IWS wire rope was carried out and the results of simulation and experiment compared.展开更多
The microstructure and nano-tribological properties of 316 austenitic stainless steel have been investigated by using the in situ nano–mechanical testing system TriboIndenter, in which six different normal forces wer...The microstructure and nano-tribological properties of 316 austenitic stainless steel have been investigated by using the in situ nano–mechanical testing system TriboIndenter, 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.展开更多
The influence of MoS_2 on the tribology characteristic parameter of Ni60A/MoS_2composite lubricating coating was researched on the UMT-2 fretting abrasion tester (USA).The result shows that with increasing content of ...The influence of MoS_2 on the tribology characteristic parameter of Ni60A/MoS_2composite lubricating coating was researched on the UMT-2 fretting abrasion tester (USA).The result shows that with increasing content of MoS_2, the hardness curve of the compositecoating decreases and the trend accelerates.Under the same experimental conditions,the mass loss of plasma spray composite coating without adding MoS_2 is 1.27×10^(-2) mg.When the amount of MoS_2 reaches 35%, the mass loss is 0.96×10^(-2) mg.It can be seenthat adding MoS_2 phase can improve the wear resistance, the amplitude of which is closeto 30%.The friction coefficient of plasma spray composite coating without adding MoS_2 is0.23.Adding MoS_2 could decrease the friction coefficient of the coating and presents adowntrend.When the mass fraction is 35%, the friction coefficient is the smallest (0.13),and the range is doubled.展开更多
The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-...The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-directional sliding motions. The worn surface and wear particles produced in these two lubricants were analyzed. Sliding motion pattern affected the friction coefficients lubricated with plasma,while seldom affected that lubricated with brine. UHMWPE lubricated with plasma showed about half of the wear rate of that lubricated with brine. The two rates were 0.75 pg/m and 2.19 pg/m for the two motion patterns,respectively. However,wear particles generated in plasma included a greater amount of small particles,compared to that in brine. In uni-directional reciprocation,the main wear mechanism is ploughing both in plasma and in brine. In bi-directional sliding modes,the significant characteristic is ripples on the worn surface in plasma,while there are oriented fibers on the worn surface in brine.展开更多
Friction and wear of GCr15 under cross-sliding condition is tested on a ball-on-disc wear test machine. Thisresult shows that the cross-sliding of friction pair leads to different friction and wear behavior. For the c...Friction and wear of GCr15 under cross-sliding condition is tested on a ball-on-disc wear test machine. Thisresult shows that the cross-sliding of friction pair leads to different friction and wear behavior. For the condition de-scribed in this paper, the friction coefficients with ball reciprocating are smaller than that without ball reciprocating.The friction coefficients increase with the increase of reciprocating frequency.. The wear weight loss of the ball sub-jected reciprocating sliding decreases, however, the wear weight loss of disc against the reciprocating ball increases. Incross-sliding friction, the worn surfaces of the ball show crinkle appearance along the circumferential sliding traces.Delaminating of small strip debris is formed along the plowing traces on the disc worn surface. The plowing furrow onthe disc surfaces looks deeper and wider than that without reciprocating sliding. The size of wear particles fromcross-sliding wear is larger than those without reciprocating sliding.展开更多
基金Projects 2007CB607605 supported by the Major State Basic Research and Development Program of China50535050, 50225519, 50405042 by the National Natural Science Foundation of China2005B032 by the Science Foundation of China University of Mining and Technology
文摘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 ni-trogen 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 di-mension 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 de-crease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.
基金Project 07KJB430116 supported by the Natural Science Foundation of High University in Jiangsu Province
文摘Using ANSYS software, we developed a modeling program for several kinds of wire ropes with metal cores and built a geometric model for the 6×19 IWS wire rope. Through proper grid partitioning, a finite element model for calculating the deforma-tion of wire rope was obtained. Completely constraining one end of the wire rope and applying an axial force to the other end, we established the boundary conditions for solving the model. In addition, we numerically simulated the stress and deformation of the wire, obtaining the deformation distribution of each wire within the wire rope under different laying directions. At the end, a tensile test of the 6×19 IWS wire rope was carried out and the results of simulation and experiment compared.
基金Project 50535050 supported by National Natural Science Foundation of China
文摘The microstructure and nano-tribological properties of 316 austenitic stainless steel have been investigated by using the in situ nano–mechanical testing system TriboIndenter, 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.
基金Supported by the National Key Basic Research Development Program of China(973 Program)(2007CB607605)the National Natural Science Foundation of China(50965008)
文摘The influence of MoS_2 on the tribology characteristic parameter of Ni60A/MoS_2composite lubricating coating was researched on the UMT-2 fretting abrasion tester (USA).The result shows that with increasing content of MoS_2, the hardness curve of the compositecoating decreases and the trend accelerates.Under the same experimental conditions,the mass loss of plasma spray composite coating without adding MoS_2 is 1.27×10^(-2) mg.When the amount of MoS_2 reaches 35%, the mass loss is 0.96×10^(-2) mg.It can be seenthat adding MoS_2 phase can improve the wear resistance, the amplitude of which is closeto 30%.The friction coefficient of plasma spray composite coating without adding MoS_2 is0.23.Adding MoS_2 could decrease the friction coefficient of the coating and presents adowntrend.When the mass fraction is 35%, the friction coefficient is the smallest (0.13),and the range is doubled.
基金Project 50535050 supported by the National Natural Science Foundation of China
文摘The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-directional sliding motions. The worn surface and wear particles produced in these two lubricants were analyzed. Sliding motion pattern affected the friction coefficients lubricated with plasma,while seldom affected that lubricated with brine. UHMWPE lubricated with plasma showed about half of the wear rate of that lubricated with brine. The two rates were 0.75 pg/m and 2.19 pg/m for the two motion patterns,respectively. However,wear particles generated in plasma included a greater amount of small particles,compared to that in brine. In uni-directional reciprocation,the main wear mechanism is ploughing both in plasma and in brine. In bi-directional sliding modes,the significant characteristic is ripples on the worn surface in plasma,while there are oriented fibers on the worn surface in brine.
文摘Friction and wear of GCr15 under cross-sliding condition is tested on a ball-on-disc wear test machine. Thisresult shows that the cross-sliding of friction pair leads to different friction and wear behavior. For the condition de-scribed in this paper, the friction coefficients with ball reciprocating are smaller than that without ball reciprocating.The friction coefficients increase with the increase of reciprocating frequency.. The wear weight loss of the ball sub-jected reciprocating sliding decreases, however, the wear weight loss of disc against the reciprocating ball increases. Incross-sliding friction, the worn surfaces of the ball show crinkle appearance along the circumferential sliding traces.Delaminating of small strip debris is formed along the plowing traces on the disc worn surface. The plowing furrow onthe disc surfaces looks deeper and wider than that without reciprocating sliding. The size of wear particles fromcross-sliding wear is larger than those without reciprocating sliding.
