The microstructure of a Ti-48Al alloy cooled after a solution treatment in
the alpha-field is influenced by the cooling rate. In order to characterize
the lamellar structure and to know the values of alpha(2)-volume fraction,
width of alpha(2)-lamellae, and interlamellar spacing, we developed a meth
od of measurement based on an observation of laths in the scanning electron
microscope. The study revealed the heterogeneous distribution of the lamel
lar structure in a commercial purity Ti-48Al alloy cooled from the alpha-fi
eld at a rate of 35 degrees C/min. The evolution of alpha(2)-volume fractio
n with the cooling rate showed that the microhardness is determined by the
quantity of alpha(2)-phase. The values of yield stress also increased and w
ere all the less scattered as the structure became more perfectly lamellar.
Yield stress and interlamellar spacing are linked by a Hall-Fetch relation
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