Effects of Centrifugal Forces and Casting Modulus on Structures and Mechanical Properties of Ti-6Al-4V Alloy.

The present investigation mainly focuses on effects of centrifugal forces and casting modulus on structures and mechanical properties of Ti-6Al-4V alloy formed under different vertical centrifugal casting conditions in graphite molds. Mold rotating rates of 0, 110 and 210 r/min were adopted in the experiment. Results show that grain size and lamellar thickness decrease with the decreasing of casting modulus or the increasing of centrifugal force, while tensile strengths are considerably enhanced, but the elongation of the casting shows the opposite changing trend. The quantitative relationships among gravity coefficient, casting modulus and structures or mechanical properties of Ti-6Al-4V alloy have been obtained. As the comparison of Ti-6Al-4V alloy cast in graphite mold under gravity field, the structures of stepped casting in metal mold were also investigated. It is found that the grain size or lamellar thickness in the two molds shows the same changing trend with the cooling rate, and the quantitative relationships between structures and cooling rates have been obtained. [ABSTRACT FROM AUTHOR]