The densification of titanium powders is investigated in uniaxial die press
ing experiments carried out isothermally at 980 degrees C (in the B-field o
f titanium) and during thermal cycling between 860 and 980 degrees C (about
the alpha/beta phase transformation of titanium). Thermal cycling is found
to enhance densification kinetics through the emergence of transformation-
mismatch plasticity (the mechanism responsible for transformation superplas
ticity) as a densification mechanism. The isothermal hot-pressing data comp
are favorably with existing models of powder densification, and these model
s are successfully adapted to the case of transformation-mismatch plasticit
y during thermal cycling. Similar conclusions are reached for the densifica
tion of titanium powders containing 1, 5, or 10 vol.% ZrO2 particles. Howev
er, the addition of ZrO2 hinders densification by dissolving in the titaniu
m matrix during the hot-pressing procedure. (C) 2000 Acta Metallurgica Inc.
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