The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigat...The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigated. Experimental results show that the metal-plastic multilayer composite filled with glass fiber exhibits excellent friction and impact wear properties when using rare earth elements as surface modifier for the surface treatment of glass fiber.展开更多
The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces wer...The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.展开更多
The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination,...The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination, scanning electron microscopic examination and drop ball test. The results show that it can obtain extractive impact fracture resistance after proper heat treatment. More advantages were obtained for the ball worked in the condition of low-imp ductility act. The main reasons are the function of RE and the change in morphology of eutectic carbide network.展开更多
Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 3...Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.展开更多
Alloying is an important method to improve properties of casts. The influences of Mo and RE on the mechanical properties of ZG30Cr were investigated in this work. A good comprehensive mechanical properties of the allo...Alloying is an important method to improve properties of casts. The influences of Mo and RE on the mechanical properties of ZG30Cr were investigated in this work. A good comprehensive mechanical properties of the alloy with 0.3% Mo and 0.1% RE were obtained. The elongation, tensile strength, impact toughness and hardness of the alloy reaches 7. 21%, 577.49 MPa, 91.7 J·cm-2 and HRC 24.6, respectively.展开更多
The effect of heat treatment on hardness and impact toughness of CuCr containing rare earth alloy was studied by means of metallographic, XRD, SEM/EDX, TEM and mechanical property test. The results show that the heat ...The effect of heat treatment on hardness and impact toughness of CuCr containing rare earth alloy was studied by means of metallographic, XRD, SEM/EDX, TEM and mechanical property test. The results show that the heat treatment can change the hardness of CuCr alloy, and has smaller influence to its impact toughness. The optimum properties of CuCr containing RE alloy could be obtained by aging treatment at 500 ℃ for 2 h. And the causes of the above changes and the function of RE were analyzed.展开更多
The morphology of carbides, as well as the generation and propagation of fatigue cracks in a wear resistant white cast iron after impact fatigue test were observed by means of optical microscope and SEM, and the relat...The morphology of carbides, as well as the generation and propagation of fatigue cracks in a wear resistant white cast iron after impact fatigue test were observed by means of optical microscope and SEM, and the relationship among the content of RE (rare earths) in the wear resistant white cast iron and the heating temperature as well as the length and propagation speed of the fatigue cracks were determined. Based on the obtained results, the effect of RE modification and heat treatment on the impact fatigue property was further studied. Experimental results show that addition of RE can defer the time required for the generation of fatigue cracks, reduce their propagation speed and increase the impact fatigue resistance. The aforesaid effect is more noticeable in case of combined RE modification with heat treatment, which can be attributed to the variation in morphology and the distribution of the eutectic carbide network.展开更多
An apparatus of zone melting unidirectional solidification with a steep temperature gradient and an impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impact fatigue proper...An apparatus of zone melting unidirectional solidification with a steep temperature gradient and an impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impact fatigue properties of the low Cr white cast iron were investigated.Experimental results showed that the modi- fying effect of RE elements was remarkable on the M3C carbides.With the addition of RE elements in the low Cr iron,a lot of plate-like carbides were transformed into lath-like and rod-like ones.The higher the content of RE elements was,the more was the fraction of the lath-like and rod-like carbides.In the low Cr white cast iron,the RE modifying agent can efficiently increase the impact fatigue resistance and decrease the crack growth rate and delay the time of incipient cracking.With the increase of the content of RE elements in the low Cr cast iron,the impact fatigue resistance increased greatly and the crack growth rate decreased rap- idly.展开更多
The existing data on the confirmed extraterrestrial impacts and geomagnetic reversals are examined. Differential rotation of the inner core of the Earth relative to the rest of the planet has been observed through sei...The existing data on the confirmed extraterrestrial impacts and geomagnetic reversals are examined. Differential rotation of the inner core of the Earth relative to the rest of the planet has been observed through seismic records. Differential rotation between the inner and outer core is thought to be related to the geomagnetic field of the Earth. Extraterrestrial impacts with the surface of the Earth have been shown to cause changes in this differential rotation. It is shown in this paper that there is a strong correlation between the dates of major impacts and geomagnetic reversals. This strongly supports the possibility of major extraterrestrial impacts being one of the causes of geomagnetic reversals as has been suggested previously.展开更多
A technique of treating steel with rare earth fluoride complex additives(REFCA),effects and influnce factors have been studied.REFCA play a role on controlling inclusion morphology,purifying the molten steel and impro...A technique of treating steel with rare earth fluoride complex additives(REFCA),effects and influnce factors have been studied.REFCA play a role on controlling inclusion morphology,purifying the molten steel and improving properties of steel.The optimum composition of REFCA is REF_3 42%;CaO 33%;SiCa 25%,and the amount of REF_3 is 0.5 wt%～0.6 wt% of steel.展开更多
文摘The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigated. Experimental results show that the metal-plastic multilayer composite filled with glass fiber exhibits excellent friction and impact wear properties when using rare earth elements as surface modifier for the surface treatment of glass fiber.
文摘The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.
文摘The low-energy multi-impact fracture resistance of the cross rolled low chromium cast semi-steel containing RE grinding balls was studied. Moreover, its damage mode was analyzed by means of metallographic examination, scanning electron microscopic examination and drop ball test. The results show that it can obtain extractive impact fracture resistance after proper heat treatment. More advantages were obtained for the ball worked in the condition of low-imp ductility act. The main reasons are the function of RE and the change in morphology of eutectic carbide network.
文摘Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.
基金Project supported by the Research Foundation for the Key Field of the Education Department of Inner Mongolia Autonomous Region (ZL0005)
文摘Alloying is an important method to improve properties of casts. The influences of Mo and RE on the mechanical properties of ZG30Cr were investigated in this work. A good comprehensive mechanical properties of the alloy with 0.3% Mo and 0.1% RE were obtained. The elongation, tensile strength, impact toughness and hardness of the alloy reaches 7. 21%, 577.49 MPa, 91.7 J·cm-2 and HRC 24.6, respectively.
文摘The effect of heat treatment on hardness and impact toughness of CuCr containing rare earth alloy was studied by means of metallographic, XRD, SEM/EDX, TEM and mechanical property test. The results show that the heat treatment can change the hardness of CuCr alloy, and has smaller influence to its impact toughness. The optimum properties of CuCr containing RE alloy could be obtained by aging treatment at 500 ℃ for 2 h. And the causes of the above changes and the function of RE were analyzed.
文摘The morphology of carbides, as well as the generation and propagation of fatigue cracks in a wear resistant white cast iron after impact fatigue test were observed by means of optical microscope and SEM, and the relationship among the content of RE (rare earths) in the wear resistant white cast iron and the heating temperature as well as the length and propagation speed of the fatigue cracks were determined. Based on the obtained results, the effect of RE modification and heat treatment on the impact fatigue property was further studied. Experimental results show that addition of RE can defer the time required for the generation of fatigue cracks, reduce their propagation speed and increase the impact fatigue resistance. The aforesaid effect is more noticeable in case of combined RE modification with heat treatment, which can be attributed to the variation in morphology and the distribution of the eutectic carbide network.
文摘An apparatus of zone melting unidirectional solidification with a steep temperature gradient and an impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impact fatigue properties of the low Cr white cast iron were investigated.Experimental results showed that the modi- fying effect of RE elements was remarkable on the M3C carbides.With the addition of RE elements in the low Cr iron,a lot of plate-like carbides were transformed into lath-like and rod-like ones.The higher the content of RE elements was,the more was the fraction of the lath-like and rod-like carbides.In the low Cr white cast iron,the RE modifying agent can efficiently increase the impact fatigue resistance and decrease the crack growth rate and delay the time of incipient cracking.With the increase of the content of RE elements in the low Cr cast iron,the impact fatigue resistance increased greatly and the crack growth rate decreased rap- idly.
文摘The existing data on the confirmed extraterrestrial impacts and geomagnetic reversals are examined. Differential rotation of the inner core of the Earth relative to the rest of the planet has been observed through seismic records. Differential rotation between the inner and outer core is thought to be related to the geomagnetic field of the Earth. Extraterrestrial impacts with the surface of the Earth have been shown to cause changes in this differential rotation. It is shown in this paper that there is a strong correlation between the dates of major impacts and geomagnetic reversals. This strongly supports the possibility of major extraterrestrial impacts being one of the causes of geomagnetic reversals as has been suggested previously.
文摘A technique of treating steel with rare earth fluoride complex additives(REFCA),effects and influnce factors have been studied.REFCA play a role on controlling inclusion morphology,purifying the molten steel and improving properties of steel.The optimum composition of REFCA is REF_3 42%;CaO 33%;SiCa 25%,and the amount of REF_3 is 0.5 wt%～0.6 wt% of steel.
