Shoichi Tokuda1 and Hiromichi Kawahara2
1Asada Fundamental Research Laboratory, Kobe Steel Ltd., Kobe
Following a previous work on the microsegregation of β stabilizing elements in binary and commercial titanium alloys, the effects of cooling rate from the β phase and the content of the alloying element Al on the microsegregation of Al were quantitatively investigated on Ti-Al binary alloys and in commercial titanium alloys such as Ti-8Al-1Mo-1V, Ti-6Al-4V, Ti-5Al-2Cr-1Fe, Ti-4Al-3Mo-1V and Ti-16V-2.5Al using an electron probe microanalyser (EPMA). Results are as follows:
(1) Microsegregation of Al is affected by the cooling rate from β phase, but is not greatly affected by the content of Al.
(2) In the examination with parameters such as the segregation index, the effective distribution coefficient and the α stabilizing rate, the genetic trend of microsegregation of Al is smaller than that of β stabilizing elements.
(3) In single phase alloys the concentration of Al is high inside grains and is low in the neighbourhood of boundaries. In two phase (α + β ) alloys, the concentration of Al is high inside grains and is low in the β phase.
(4) The genetic trend of microsegregation of Al in commercial titanium alloys is scarcely affected by kind and amount of the co-existing β stabilizing element.
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