Thermodynamic properties of Ti-Al intermetallics

Abstract

Thermodynamic properties of the titanium-aluminum system have been investigated over the entire composition range. A solid-state reversible galvanic cell employing a calcium fluoride (CaF2) solid electrolyte and an Al-CaAlF7 reference electrode was used in the temperature range 820-900 K for solid alloys containing 31.3, 47.9, 64.7, 73.6 and 99.0 atom percent aluminum. Experimental results of the activities of Al in the alloys showed a large negative deviation from ideal behavior. For instance the activity of Al in an alloy with 0.48 atomic fraction of Al was determined to be 2.98×10-3 at 850 K. © 2001 Elsevier Science B.V.