Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion cra...Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth (SCCG) behavior of their interfaces with Ti6AI4V was investigated in simulated body fluid (SBF) with the objective of discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicated that crack growth rates in Ti6AI4V/glass/Ti6AI4V sandwich specimens were nearly the same as or slightly lower than those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off the interface, suggesting that the Ti6AI4V/glass interface has relatively good crack-growth resistance. Mechanistically, interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, with no discernible effect of bioactivity on the SCCG behavior being observed.展开更多
High speed impact experiments of rectangular plate-shaped Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 bulk metallic glass（BMG） were performed using a two-stage light gas gun.Under spherical shock waves with impact velocities ...High speed impact experiments of rectangular plate-shaped Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 bulk metallic glass（BMG） were performed using a two-stage light gas gun.Under spherical shock waves with impact velocities ranging from 0.503 km/s to 4.917 km/s,obvious traces of laminated spallation at the back（free） surface and melting（liquid droplets） at the impact point were observed.The angles about 0掳,17掳,36掳,and 90掳to the shocking direction were shown in the internal samples because of the interaction between the compressive shock waves and the rarefaction waves.The compressive normal stress was found to induce the consequent temperature rise in the core of the shear band.展开更多
Heat-ray absorbing film is used to be bonded on the existing sheet glasses of the windows.It is effective for air-conditioning energy saving against the global warming,because it absorbs heat-ray in the thin film and ...Heat-ray absorbing film is used to be bonded on the existing sheet glasses of the windows.It is effective for air-conditioning energy saving against the global warming,because it absorbs heat-ray in the thin film and decreases the incoming heat-ray into the room.On the other hand,the sheet glasses increase the temperature at the surface which the sheet is bonded and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stresses accurately in order to develop the heat-ray absorbing film with higher performance and without heat cracks.In this paper,the analysis model is treated as the two-layer plate of the conventional soda sheet glass and the heat-ray absorbing film with different absorptivities.The unsteady temperature and thermal stresses are analyzed and calculated numerically.The influence of the patch side,which the heat-ray absorbing film is bonded at the exterior side or the interior side,on the heat-ray absorbing performance and the thermal stresses is discussed.It is found that the alternative patch side has no effect on the heat-ray absorbing performance and that the patch side is recommended to be interior side from a view point of decreasing thermal stresses against the heat crack of glasses.展开更多
Heat-ray absorbing sheet glass can decrease electric energy used for air-conditioning by controling the incoming heat-ray through windows into the rooms.On the other hand,the glasses increase the temperature and somet...Heat-ray absorbing sheet glass can decrease electric energy used for air-conditioning by controling the incoming heat-ray through windows into the rooms.On the other hand,the glasses increase the temperature and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stress accurately in order to develop heat-ray absorbing sheet glasses with higher performance and without heat cracks.A conventional design manual at field site treats the steady state and the thermal boundary condition that all heat-rays are absorbed at glass surface.In this paper,it is assumed that the heat-ray is absorbed over all the plate thickness.The idea of the local absorptibity per unit length is introduced.The modeling of internal heat absorbing process is proposed.It can explain well that the total absorptivity depends on the plate thickness.The temperature and the thermal stresses are calculated and discussed.Sudden weather changes such as rain and/or wind after the glass is heated to be steady state are also discussed.Those weather changes are treated with the change of amount of absorbed heat-ray and/or the change of heat transfer coefficient between the glass surface and the outside atmosphere.展开更多
文摘Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth (SCCG) behavior of their interfaces with Ti6AI4V was investigated in simulated body fluid (SBF) with the objective of discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicated that crack growth rates in Ti6AI4V/glass/Ti6AI4V sandwich specimens were nearly the same as or slightly lower than those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off the interface, suggesting that the Ti6AI4V/glass interface has relatively good crack-growth resistance. Mechanistically, interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, with no discernible effect of bioactivity on the SCCG behavior being observed.
基金Project supported by the National Basic Research Program of China (Grant No. 2010CB731600)
文摘High speed impact experiments of rectangular plate-shaped Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 bulk metallic glass（BMG） were performed using a two-stage light gas gun.Under spherical shock waves with impact velocities ranging from 0.503 km/s to 4.917 km/s,obvious traces of laminated spallation at the back（free） surface and melting（liquid droplets） at the impact point were observed.The angles about 0掳,17掳,36掳,and 90掳to the shocking direction were shown in the internal samples because of the interaction between the compressive shock waves and the rarefaction waves.The compressive normal stress was found to induce the consequent temperature rise in the core of the shear band.
文摘Heat-ray absorbing film is used to be bonded on the existing sheet glasses of the windows.It is effective for air-conditioning energy saving against the global warming,because it absorbs heat-ray in the thin film and decreases the incoming heat-ray into the room.On the other hand,the sheet glasses increase the temperature at the surface which the sheet is bonded and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stresses accurately in order to develop the heat-ray absorbing film with higher performance and without heat cracks.In this paper,the analysis model is treated as the two-layer plate of the conventional soda sheet glass and the heat-ray absorbing film with different absorptivities.The unsteady temperature and thermal stresses are analyzed and calculated numerically.The influence of the patch side,which the heat-ray absorbing film is bonded at the exterior side or the interior side,on the heat-ray absorbing performance and the thermal stresses is discussed.It is found that the alternative patch side has no effect on the heat-ray absorbing performance and that the patch side is recommended to be interior side from a view point of decreasing thermal stresses against the heat crack of glasses.
文摘Heat-ray absorbing sheet glass can decrease electric energy used for air-conditioning by controling the incoming heat-ray through windows into the rooms.On the other hand,the glasses increase the temperature and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stress accurately in order to develop heat-ray absorbing sheet glasses with higher performance and without heat cracks.A conventional design manual at field site treats the steady state and the thermal boundary condition that all heat-rays are absorbed at glass surface.In this paper,it is assumed that the heat-ray is absorbed over all the plate thickness.The idea of the local absorptibity per unit length is introduced.The modeling of internal heat absorbing process is proposed.It can explain well that the total absorptivity depends on the plate thickness.The temperature and the thermal stresses are calculated and discussed.Sudden weather changes such as rain and/or wind after the glass is heated to be steady state are also discussed.Those weather changes are treated with the change of amount of absorbed heat-ray and/or the change of heat transfer coefficient between the glass surface and the outside atmosphere.
