Effect of primary α phase fraction on tensile behavior of IMI 834 alloy

In the present work, the tensile behavior of IMI 834 alloy with varying primary alpha (alpha(p)) fraction in the transformed beta matrix was studied at room temperature. Variation in alpha(p) phase fraction was obtained by changing the solution treatment temperature of the material in the alpha+beta region from 1288K to 1333K. All the solution treated samples were then aged at 973K for 2hrs and cooled in air. Final microstructures consisted of various alpha(p) fractions (0.045 to 22 %) along with incoherent silicide precipitate (Ti, Zr)(6)Si-3 and coherent Ti3Al precipitates which resulted in bimodal and lamellar microstructures. The ap phase fraction for bimodal microstructure was ranging from 3 to 22 % and that for lamellar microstructure 0 to 1 %. Tensile test results show that tensile strength increased with increase in alpha(p) up to - 15 % and further increase in alpha(p) from similar to 15 % to 22 % lead to decrease in tensile strength. The tensile test result also shows improvement in strain hardening with increase in alpha(p). The higher tensile strength for samples with alpha(p) fraction up to similar to 15 % and lower tensile strength for sample with alpha(p) fraction similar to 15% - 22 % is attributed to effective slip length and solute partitioning effect, respectively. (C) 2019 The Authors. Published by Elsevier B.V.