The porous titanium fiber materials with open porosity were successfully prepared by the vacuum sintering technology.The morphology characteristics of sintering neck of porous titanium fiber materials were investigate...The porous titanium fiber materials with open porosity were successfully prepared by the vacuum sintering technology.The morphology characteristics of sintering neck of porous titanium fiber materials were investigated by scanning electron microscopy(SEM).The results show that the formation and growth of sintering neck of porous titanium fiber material approximately follow the rule that the primary mechanism is grain boundary diffusion and subsidiary mechanisms are other diffusion mechanisms during the sintering process.The formation and growth of the sintering neck depend mainly on the sintering temperature and slightly on the soaking time.The sintering system of porous titanium fiber material was determined and the equation of the sintering neck′s length was established.展开更多
The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The...The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The results show that with increasing hydrogen content,the stretching and bending extent of fully lamellar microstructures including ot lamellas and acicular hydride continued to increase,the morphology of dynamic recrystallization(DRX)grains tended to change from approximately equiaxed to large lamellar shape,and the quantity of DRX grains and recrystallization degree of grains increased obviously.A large number of dislocations concentrated in the vicinity of the hydride.Steady stress was decreased continuously with increasing hydrogen content,while peak stress of the hydrogenated 0.12 wt.% H weld zone was decreased to the minimum value and then increased slowly.A slight decrease in flow stress of the hydrogenated 0.05 wt.% H weld zone was caused by limited increase in the volume fraction of softer βphase.Hydrogen-induced DRX of a phase and improved dislocation movement by strong interaction between the hydride and dislocation directly resulted in a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone.Solute hydrogen also finitely contributed to a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone by promoted local softening,which induced continuous DRX and more movable dislocations to participate in slipping or climbing.The reinforcement effect and plastic deformation of the hydride and solution strengthening of P phase induced by solute hydrogen finally led to the increase in flow stress of the hydrogenated 0.21 wt.% H weld zone in its true strain range from 0 to 0.36.展开更多
基金Item Sponsored by National Natural Science Foundation of China(51304153)Natural Science Foundation of Shaanxi Province of China(2012JM6017)
文摘The porous titanium fiber materials with open porosity were successfully prepared by the vacuum sintering technology.The morphology characteristics of sintering neck of porous titanium fiber materials were investigated by scanning electron microscopy(SEM).The results show that the formation and growth of sintering neck of porous titanium fiber material approximately follow the rule that the primary mechanism is grain boundary diffusion and subsidiary mechanisms are other diffusion mechanisms during the sintering process.The formation and growth of the sintering neck depend mainly on the sintering temperature and slightly on the soaking time.The sintering system of porous titanium fiber material was determined and the equation of the sintering neck′s length was established.
基金The authors would like to gratefully acknowledge that this work was supported by the China Postdoctoral Science Foundation(Grant No.2020M672306)National Natural Science Foundation of China(Grant Nos.51874225 and 51671152).
文摘The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The results show that with increasing hydrogen content,the stretching and bending extent of fully lamellar microstructures including ot lamellas and acicular hydride continued to increase,the morphology of dynamic recrystallization(DRX)grains tended to change from approximately equiaxed to large lamellar shape,and the quantity of DRX grains and recrystallization degree of grains increased obviously.A large number of dislocations concentrated in the vicinity of the hydride.Steady stress was decreased continuously with increasing hydrogen content,while peak stress of the hydrogenated 0.12 wt.% H weld zone was decreased to the minimum value and then increased slowly.A slight decrease in flow stress of the hydrogenated 0.05 wt.% H weld zone was caused by limited increase in the volume fraction of softer βphase.Hydrogen-induced DRX of a phase and improved dislocation movement by strong interaction between the hydride and dislocation directly resulted in a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone.Solute hydrogen also finitely contributed to a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone by promoted local softening,which induced continuous DRX and more movable dislocations to participate in slipping or climbing.The reinforcement effect and plastic deformation of the hydride and solution strengthening of P phase induced by solute hydrogen finally led to the increase in flow stress of the hydrogenated 0.21 wt.% H weld zone in its true strain range from 0 to 0.36.
