Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
236248 | Powder Technology | 2014 | 6 Pages |
•Micro-fine TiAl based alloyed powders can be prepared by fluidized bed jet milling.•Rising frequency at 5600–8400 rpm makes average size decrease in the range of 5–18 μm.•At or above 5600 rpm, more finer flaky debris is produced due to abrasion breakage.•Decreasing grinding gas pressure causes the rise of the flaky debris proportion.
Micro-fine high Nb containing TiAl alloyed powders were prepared by using fluidized bed jet milling from the pre-crushed Ti–45Al–8.5Nb–0.2W–0.2B–0.02Y(at.%) ingot. The effects of process parameters on the powder characteristics were investigated. The results show that the particle characteristics are mainly determined by classifier frequency. At or above 5600 rpm, the ground powders are composed of coarse block-shaped particles and finer flaky debris, with particle number-average diameter lower than 18 μm. With the increase of classifier frequency and the decrease of grinding gas pressure, the amount of flaky debris formed under abrasion mechanism gradually increases, which causes the obvious decrease of the powder number-average diameter, distribution uniformity, and sphericity degree. With the classifier frequency of 8400 rpm and grinding gas pressure of 0.55 MPa, the obtained powders possess the minimum particle size of 5.32 μm, with a uniformity level of 0.38 and a Wadell's sphericity factor of 0.820.
Graphical abstractCoarse particles are dominated by destructive breakage with fracture mode of interlamellar and slightly deviated translamellar. As particle size reduces, abrasion and fatigue breakage tend to play a leading role. With the increase of classifier frequency and decrease of grinding gas pressure, the amount of flaky debris formed under abrasion increases.Figure optionsDownload full-size imageDownload as PowerPoint slide