It was found that typical Nbss /Nb5Si3 eutectic lamellar structure formed in the Nb-Mo-Si alloy. The interface between Nbss and Nb5Si3 phases was so strong that the alloy fractured mainly in the cleavage mode. In this...It was found that typical Nbss /Nb5Si3 eutectic lamellar structure formed in the Nb-Mo-Si alloy. The interface between Nbss and Nb5Si3 phases was so strong that the alloy fractured mainly in the cleavage mode. In this paper, the fourth element was added with the aim of modifying interface structure. The microstructural characterization and the fracture toughness of Nb-17Si-10Mo ternary alloy doped with Ga, In, Zn and V, respectively, were investigated. It was revealed that the lamellar structure maintained with the addition of Ga and In, whereas it changed slightly with Zn and V additions. Moreover, a little increase in fracture toughness of Nb-17Si-10Mo ternary alloy was obtained through the addition of Ga and Zn.展开更多
The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that dopi...The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that doping thetransition metal elements can effectively change the band structure and enable the alloysystem to show the stronger metallic feature. The dopants of V, Cr and Mn increase s-orbital component of Ti and Al in bonding orbital, therefore, there is more sphericalelectronic clound and weakly directional bonds in the crystal, which improve the duictil-ity of the alloy, Nb or Ta makes stronger bonding with Ti and Al, which improvestrength and oxidation resistance of the alloy.展开更多
基金Supported by the Aviation Science Foundation of China (Grant No 200601104)
文摘It was found that typical Nbss /Nb5Si3 eutectic lamellar structure formed in the Nb-Mo-Si alloy. The interface between Nbss and Nb5Si3 phases was so strong that the alloy fractured mainly in the cleavage mode. In this paper, the fourth element was added with the aim of modifying interface structure. The microstructural characterization and the fracture toughness of Nb-17Si-10Mo ternary alloy doped with Ga, In, Zn and V, respectively, were investigated. It was revealed that the lamellar structure maintained with the addition of Ga and In, whereas it changed slightly with Zn and V additions. Moreover, a little increase in fracture toughness of Nb-17Si-10Mo ternary alloy was obtained through the addition of Ga and Zn.
文摘The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that doping thetransition metal elements can effectively change the band structure and enable the alloysystem to show the stronger metallic feature. The dopants of V, Cr and Mn increase s-orbital component of Ti and Al in bonding orbital, therefore, there is more sphericalelectronic clound and weakly directional bonds in the crystal, which improve the duictil-ity of the alloy, Nb or Ta makes stronger bonding with Ti and Al, which improvestrength and oxidation resistance of the alloy.