The Ti-47Al-2Nb-2Cr-0.2W alloy sheets were obtained by hot pack rolling. The as-rolled sheet has an inhomogeneous duplex microstructure composed of elongated gamma grains and lamellar colonies. Heat treatments were co...The Ti-47Al-2Nb-2Cr-0.2W alloy sheets were obtained by hot pack rolling. The as-rolled sheet has an inhomogeneous duplex microstructure composed of elongated gamma grains and lamellar colonies. Heat treatments were conducted on the as-rolled sheets. The results show that the microstructures with different sizes and grain boundary morphologies were developed after different heat treatments. A coarse fully lamellar structure can be refined if the heating time, together with the cooling rate, is appropriately controlled. The grain growth exponent is found to be approximately 0.2, and the activation energy of grain boundary migration of the alloy is around 225 kJ/mol.展开更多
A facile strategy is established for constructing composite nanostructure with ultrasmall Pt nanoparticles(NPs) of ~2 nm in diameter being homogeneously embedded in N-doped carbon nanosheets. The strong coordination b...A facile strategy is established for constructing composite nanostructure with ultrasmall Pt nanoparticles(NPs) of ~2 nm in diameter being homogeneously embedded in N-doped carbon nanosheets. The strong coordination between Pt atoms in cisplatin and N atoms in pyrrole contributes to the robust embedding of Pt NP into the N-doped carbon nanosheets after annealing. Such a unique partially-embedding structure facilitates the active site exposure while stabilizing the ultrasmall Pt NPs, leading to the comparable electrochemical activities for hydrogen evolution and oxygen reduction reactions, and substantially improves durability performance compared to that of the state-of-the-art Pt/C(20 wt%).展开更多
基金Project(2011CB605505)supported by the National Basic Research Program of ChinaProject(51174233)supported by the National Natural Science Foundation of China
文摘The Ti-47Al-2Nb-2Cr-0.2W alloy sheets were obtained by hot pack rolling. The as-rolled sheet has an inhomogeneous duplex microstructure composed of elongated gamma grains and lamellar colonies. Heat treatments were conducted on the as-rolled sheets. The results show that the microstructures with different sizes and grain boundary morphologies were developed after different heat treatments. A coarse fully lamellar structure can be refined if the heating time, together with the cooling rate, is appropriately controlled. The grain growth exponent is found to be approximately 0.2, and the activation energy of grain boundary migration of the alloy is around 225 kJ/mol.
基金supported by the National Key Basic Research Program of China(2013CB933200)the Natural Science Foundation of Shanghai(16ZR1440600)+1 种基金the State key laboratory of heavy oil processing(SKLOP201402003)the National Natural Science Foundation of China(U1510107)
文摘A facile strategy is established for constructing composite nanostructure with ultrasmall Pt nanoparticles(NPs) of ~2 nm in diameter being homogeneously embedded in N-doped carbon nanosheets. The strong coordination between Pt atoms in cisplatin and N atoms in pyrrole contributes to the robust embedding of Pt NP into the N-doped carbon nanosheets after annealing. Such a unique partially-embedding structure facilitates the active site exposure while stabilizing the ultrasmall Pt NPs, leading to the comparable electrochemical activities for hydrogen evolution and oxygen reduction reactions, and substantially improves durability performance compared to that of the state-of-the-art Pt/C(20 wt%).
