Abstract
Mixtures of elemental titanium and aluminium powders of overall composition TixAl1+x (x = 0.02, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8) were mechanically alloyed in a planetary-type ball mill.
Hexane was added as a process control agent to reduce powder agglomeration during milling. The as-milled powders were characterized using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. During milling, the hexane is partially dissociated, with the free carbon and hydrogen incorporated within the TixAl1 − x alloy powders in increasing amounts with increasing milling time.
The amount of incorporated carbon increases with the initial Ti content of the powder mixture, reaching a maximum of 12 wt.% incorporated into an initial Ti0.8Al0.2 powder mixture after 100 h of milling. The hydrogen is found to combine with elemental Ti to form TiH2−x, with an initial Ti0.5Al0.5 powder mixture milled for 40 h incorporating 0.95 wt.% H. The milled (TixAl1 − x + C) powder mixtures form a large fraction of amorphous phase near x = 0.5.
Annealing of the as-milled powders incorporating dissolved carbon and hydrogen produced a mixture of Al2Ti4C2, TiC and TiAl.
Hexane was added as a process control agent to reduce powder agglomeration during milling. The as-milled powders were characterized using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. During milling, the hexane is partially dissociated, with the free carbon and hydrogen incorporated within the TixAl1 − x alloy powders in increasing amounts with increasing milling time.
The amount of incorporated carbon increases with the initial Ti content of the powder mixture, reaching a maximum of 12 wt.% incorporated into an initial Ti0.8Al0.2 powder mixture after 100 h of milling. The hydrogen is found to combine with elemental Ti to form TiH2−x, with an initial Ti0.5Al0.5 powder mixture milled for 40 h incorporating 0.95 wt.% H. The milled (TixAl1 − x + C) powder mixtures form a large fraction of amorphous phase near x = 0.5.
Annealing of the as-milled powders incorporating dissolved carbon and hydrogen produced a mixture of Al2Ti4C2, TiC and TiAl.
| Original language | English |
|---|---|
| Pages (from-to) | 205-211 |
| Journal | Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing |
| Volume | 196 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 1995 |
| MoE publication type | A1 Journal article-refereed |