Hardmetals are tungsten carbide(WC)-based composites,which are made of WC as a hard phase and transition metals such as Co,Fe,or/and Ni as ductile binder matrices.Their properties can be mainly tailored through the gr...Hardmetals are tungsten carbide(WC)-based composites,which are made of WC as a hard phase and transition metals such as Co,Fe,or/and Ni as ductile binder matrices.Their properties can be mainly tailored through the grain sizes of the sintered carbides and the amount of metallic binder.As successful tool materials,hardmetals are widely applied in metal cutting,wear applications,chipless forming,stoneworking,wood,and plastic working.In 2017,about two-thirds of tungsten consumption(including recycled materials)were produced for hardmetals in the world.This paper briefly introduces the development of manufacturing technology on WC-Co hardmetals from three aspects:powder preparation,bulk densifica-tion,and performance characterization.Two special WC-Co hardmetals are also described:cobalt-enrichment zone(CEZ)hardmetals,and binderless hardmetals.Furthermore,the development prospects for manufacturing techniques of hardmetals are also presented in the end.展开更多
Shear zones in the boundary between Eastern Ghats Province (EGP) and the cratons of Singhbhum in the north and Bastar in the west provide an excellent opportunity to study the tectonics of shear zone development and i...Shear zones in the boundary between Eastern Ghats Province (EGP) and the cratons of Singhbhum in the north and Bastar in the west provide an excellent opportunity to study the tectonics of shear zone development and its timing in relation to the evolutionary history of the granulite suites. Detailed structural, microfabric and quartz C-axis patterns revealed a high temperature shear zone, at the western boundary between EGP and Bastar Craton (BC) around Paikmal. Petrological studies in this shear zone indicated decompression coeval with stretching in the sheared granulites. Geochronological constraints provided here indicate rapid exhumation of deep seated granulites in this boundary shear zone;the timing also is late in relation to the long-lived thermal (granulite formation) event in the EGP. Additionally, our geochronological data demonstrated the ~1600 Ma event in the Eastern Ghats Belt (EGB) involving sedimentation, magmatism, metamorphism and crustal anatexis, as a significant world event.展开更多
本文通过测定塑化曲线确定聚乙烯(PE)的毛细管挂丝温度范围,测试了挤出原丝和低温区域拉伸丝的力学性能和热收缩行为。结果表明,低压下的毛细管挤出工艺对 PE 丝的力学性能影响很小,而低温区域拉伸能大幅度提高原丝的力学性能,产生自增...本文通过测定塑化曲线确定聚乙烯(PE)的毛细管挂丝温度范围,测试了挤出原丝和低温区域拉伸丝的力学性能和热收缩行为。结果表明,低压下的毛细管挤出工艺对 PE 丝的力学性能影响很小,而低温区域拉伸能大幅度提高原丝的力学性能,产生自增强效应,但热收缩率明显增大。展开更多
Forming zone length (FZL) is a key parameter of the lead-clad glass fiber extrusion dies, and an unsuitable FZL will lead to breakage of the glass fiber and/or unacceptable geometric and metallographic qualities of th...Forming zone length (FZL) is a key parameter of the lead-clad glass fiber extrusion dies, and an unsuitable FZL will lead to breakage of the glass fiber and/or unacceptable geometric and metallographic qualities of the product. The optimal FZL was determined theoretically based on a mathematical model established by upper bound method, and accepted Pb-GF wire was actually obtained experimentally by symmetric side-feed extrusion at a much lower temperature than that published before. The wire has features of fine grains, uniform diameter, good coaxiality and satisfied mechanical property. The results and conclusions obtained in the research can be used to design the forming tools for lead-clad glass fiber extrusion and have significance to further research on the extrusion of other complex wires of metal-clad brittle core.展开更多
基金the Major Special Projects of Fujian Science and Technology Plan(Grant No.2017HZ0001-1)。
文摘Hardmetals are tungsten carbide(WC)-based composites,which are made of WC as a hard phase and transition metals such as Co,Fe,or/and Ni as ductile binder matrices.Their properties can be mainly tailored through the grain sizes of the sintered carbides and the amount of metallic binder.As successful tool materials,hardmetals are widely applied in metal cutting,wear applications,chipless forming,stoneworking,wood,and plastic working.In 2017,about two-thirds of tungsten consumption(including recycled materials)were produced for hardmetals in the world.This paper briefly introduces the development of manufacturing technology on WC-Co hardmetals from three aspects:powder preparation,bulk densifica-tion,and performance characterization.Two special WC-Co hardmetals are also described:cobalt-enrichment zone(CEZ)hardmetals,and binderless hardmetals.Furthermore,the development prospects for manufacturing techniques of hardmetals are also presented in the end.
文摘Shear zones in the boundary between Eastern Ghats Province (EGP) and the cratons of Singhbhum in the north and Bastar in the west provide an excellent opportunity to study the tectonics of shear zone development and its timing in relation to the evolutionary history of the granulite suites. Detailed structural, microfabric and quartz C-axis patterns revealed a high temperature shear zone, at the western boundary between EGP and Bastar Craton (BC) around Paikmal. Petrological studies in this shear zone indicated decompression coeval with stretching in the sheared granulites. Geochronological constraints provided here indicate rapid exhumation of deep seated granulites in this boundary shear zone;the timing also is late in relation to the long-lived thermal (granulite formation) event in the EGP. Additionally, our geochronological data demonstrated the ~1600 Ma event in the Eastern Ghats Belt (EGB) involving sedimentation, magmatism, metamorphism and crustal anatexis, as a significant world event.
文摘Forming zone length (FZL) is a key parameter of the lead-clad glass fiber extrusion dies, and an unsuitable FZL will lead to breakage of the glass fiber and/or unacceptable geometric and metallographic qualities of the product. The optimal FZL was determined theoretically based on a mathematical model established by upper bound method, and accepted Pb-GF wire was actually obtained experimentally by symmetric side-feed extrusion at a much lower temperature than that published before. The wire has features of fine grains, uniform diameter, good coaxiality and satisfied mechanical property. The results and conclusions obtained in the research can be used to design the forming tools for lead-clad glass fiber extrusion and have significance to further research on the extrusion of other complex wires of metal-clad brittle core.
