Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate ...Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885℃ under a pulsed pressure of 2-10 MPa within durations in the range of 2-8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the o- phase with a limit solubility of Nb, a sequence of Ti-Cu intermetallic phases and solid solutions of Ni and Cu in α＋β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 rain, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti-Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.展开更多
With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the...With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.展开更多
基金Project(51421001)supported by the National Natural Science Foundation of ChinaProjects(106112015CDJXZ138803,106112015CDJXY130003)supported by the Fundamental Research Funds for the Central Universities,China
文摘Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885℃ under a pulsed pressure of 2-10 MPa within durations in the range of 2-8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the o- phase with a limit solubility of Nb, a sequence of Ti-Cu intermetallic phases and solid solutions of Ni and Cu in α＋β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 rain, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti-Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.
基金Project(2011CB01380) supported by the National Basic Research Program of ChinaProject(51178468) supported by the National Natural Science Foundation of ChinaProject(2011G013-B) supported by Science and Technology Development of Railways Department in China
文摘With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.
