Amorphisation and phase transformations in mechanically alloyed Ti–Al powders: electron microscopy investigation
作者:
BonettiE.,
CoccoG.,
EnzoS.,
ValdrèG.,
期刊:
Materials Science and Technology
(Taylor Available online 1990)
卷期:
Volume 6,
issue 12
页码: 1258-1262
ISSN:0267-0836
年代: 1990
DOI:10.1179/mst.1990.6.12.1258
出版商: Taylor&Francis
数据来源: Taylor
摘要:
AbstractThe microstructural evolution during mechanical alloying of Ti and Al powders has been investigated by X-ray diffraction, scanning electron microscopy (SEM)–energy dispersive spectroscopy, and transmission electron microscopy (TEM). Observations by SEM showed a progressive change of the powders' morphology as a function of milling time. Observations by TEM, performed on a sample milled for 20 h, revealed the simultaneous occurrence of amorphous zones and nanocrystalline domains. The observed amorphous phase is not the final milling product. After 34 h of milling it was possible to identify by TEM fcc (a=0·41 nm) nanocrystalline zones, with a mean size of about 10 nm. By irradiating the powder milled for 20 h with high density electron beams, a suddenin situcrystallisation took place. The crystallite (fcc with a=0·41 nm) size was between 0·1 and 0·5μm.MST/1281
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