The effect of hydrogen on the deformation behavior of three typical kinds of titanium alloys, pure Ti, Ti-6Al-4V and Ti-15V-3Cr-3Al-3Sn (Ti-15-3), at high temperature has been investigated by short time creep test. XR...The effect of hydrogen on the deformation behavior of three typical kinds of titanium alloys, pure Ti, Ti-6Al-4V and Ti-15V-3Cr-3Al-3Sn (Ti-15-3), at high temperature has been investigated by short time creep test. XRD and TEM techniques are used to examine the changes in their microstructures. The results show that deformation rutes of pure Ti and Ti-6Al-4V alloy can be greatly increased by hydorgen charping due to an increase of β phase volume in their microstructures. β→α transformation is found to occur in unchanged Ti-15-3 alloy during creep process. The addition of 0. 73wt% hydrogen can completely inhibit the deformation-induced transformation and strengthen the metastable β phase in Ti-15-3 alloy, resulting in a dramatic decrease of deformation rate of this alloy at 700° C.展开更多
In this work,vortex convection is simulated using a dynamic mesh adaptation procedure.In each adaptation period,the mesh is refined in the regions where the phenomena evolve and is coarsened in the regions where the p...In this work,vortex convection is simulated using a dynamic mesh adaptation procedure.In each adaptation period,the mesh is refined in the regions where the phenomena evolve and is coarsened in the regions where the phenomena deviate since the last adaptation.A simple indicator of mesh adaptation that accounts for the solution progression is defined.The generation of dynamic adaptive meshes is based on multilevel refinement/coarsening.The efficiency and accuracy of the present procedure are validated by simulating vortex convection in a uniform flow.Two unsteady compressible turbulent flows involving blade-vortex interactions are investigated to demonstrate further the applicability of the procedure.Computed results agree well with the published experimental data or numerical results.展开更多
文摘The effect of hydrogen on the deformation behavior of three typical kinds of titanium alloys, pure Ti, Ti-6Al-4V and Ti-15V-3Cr-3Al-3Sn (Ti-15-3), at high temperature has been investigated by short time creep test. XRD and TEM techniques are used to examine the changes in their microstructures. The results show that deformation rutes of pure Ti and Ti-6Al-4V alloy can be greatly increased by hydorgen charping due to an increase of β phase volume in their microstructures. β→α transformation is found to occur in unchanged Ti-15-3 alloy during creep process. The addition of 0. 73wt% hydrogen can completely inhibit the deformation-induced transformation and strengthen the metastable β phase in Ti-15-3 alloy, resulting in a dramatic decrease of deformation rate of this alloy at 700° C.
基金National Science Foundation of China under Grant 11072113.
文摘In this work,vortex convection is simulated using a dynamic mesh adaptation procedure.In each adaptation period,the mesh is refined in the regions where the phenomena evolve and is coarsened in the regions where the phenomena deviate since the last adaptation.A simple indicator of mesh adaptation that accounts for the solution progression is defined.The generation of dynamic adaptive meshes is based on multilevel refinement/coarsening.The efficiency and accuracy of the present procedure are validated by simulating vortex convection in a uniform flow.Two unsteady compressible turbulent flows involving blade-vortex interactions are investigated to demonstrate further the applicability of the procedure.Computed results agree well with the published experimental data or numerical results.
