A fluidized bed jet milling process was used to make micro-fine high Nb-containing TiAl alloyed powders from the chippings obtained by crushing the Ti-45Al-8.5Nb-(W,B,Y) ingot.The influences of classifier frequency on...A fluidized bed jet milling process was used to make micro-fine high Nb-containing TiAl alloyed powders from the chippings obtained by crushing the Ti-45Al-8.5Nb-(W,B,Y) ingot.The influences of classifier frequency on powder characteristics were investigated.The results show that the powders with controlled average particle size can be prepared on a large scale.The powders with different sizes are all dominated by γ with aminor amount of α2-Ti3Al.The particle size significantly decreases with the classifier frequency increasing.At a classifier frequency higher than 38 Hz,the average particle size of the ground powders is lower than 25μm.The powders are composed of two differ-ent sizes of particles:shaped particles and some clastic particles,and both particle sizes meet the log-normal distribution.With the classifier frequency increasing,the both sizes decrease;meanwhile,the proportion of the clastic particles gradually increases,and the size distribution span value of the ground powders increases correspondingly.展开更多
The hot ductility was measured for a series of steels containing Nb and/or Ti with Gleeble-3500 thermo-mechanical simulator.It is found that the effect of austenitizing temperature on hot ductility of Nb-containing st...The hot ductility was measured for a series of steels containing Nb and/or Ti with Gleeble-3500 thermo-mechanical simulator.It is found that the effect of austenitizing temperature on hot ductility of Nb-containing steel is significant.As the austenitizing temperature rises up,the shape of embrittling curve (SEC) from V-shape gradually changes to U-shape,and the range of embrittling temperature widens out and the embrittling degree deepens.The SEC of Nb-containing steel is U-shaped and the embrittling temperature range is about 600-1050℃.The initial temperature of embrittlement on the right is nearly independent of carbon content.The SEC of Ti-containing steel is N-shaped and two lowest points are at about 600℃ and the A-F transformation temperature.The SEC of Nb-Ti-containing steel is basically the superposition of two shapes mentioned above.The crack on straightening in continuous casting belongs to intergranular fracture,and the crack on rolling (crack expansion) belongs to transgranular fracture.展开更多
基金financially supported by the National Nature Science Foundation of China (No.50974017)
文摘A fluidized bed jet milling process was used to make micro-fine high Nb-containing TiAl alloyed powders from the chippings obtained by crushing the Ti-45Al-8.5Nb-(W,B,Y) ingot.The influences of classifier frequency on powder characteristics were investigated.The results show that the powders with controlled average particle size can be prepared on a large scale.The powders with different sizes are all dominated by γ with aminor amount of α2-Ti3Al.The particle size significantly decreases with the classifier frequency increasing.At a classifier frequency higher than 38 Hz,the average particle size of the ground powders is lower than 25μm.The powders are composed of two differ-ent sizes of particles:shaped particles and some clastic particles,and both particle sizes meet the log-normal distribution.With the classifier frequency increasing,the both sizes decrease;meanwhile,the proportion of the clastic particles gradually increases,and the size distribution span value of the ground powders increases correspondingly.
文摘The hot ductility was measured for a series of steels containing Nb and/or Ti with Gleeble-3500 thermo-mechanical simulator.It is found that the effect of austenitizing temperature on hot ductility of Nb-containing steel is significant.As the austenitizing temperature rises up,the shape of embrittling curve (SEC) from V-shape gradually changes to U-shape,and the range of embrittling temperature widens out and the embrittling degree deepens.The SEC of Nb-containing steel is U-shaped and the embrittling temperature range is about 600-1050℃.The initial temperature of embrittlement on the right is nearly independent of carbon content.The SEC of Ti-containing steel is N-shaped and two lowest points are at about 600℃ and the A-F transformation temperature.The SEC of Nb-Ti-containing steel is basically the superposition of two shapes mentioned above.The crack on straightening in continuous casting belongs to intergranular fracture,and the crack on rolling (crack expansion) belongs to transgranular fracture.
