%0 Journal Article
%T Microstructure evolution and mechanical properties of homogenizing treated fully lamellar Ti-46Al-0.5W-0.5Si alloy
%A Chen Hui
%A Su Yanqing
%J China Foundry
%D 2013
%I Foundry Journal Agency
%X The microstructure of as-cast Ti-46Al-0.5W-0.5Si alloy exhibits significant microinhomogenetity due to the non-equilibrium solidification and low atom diffusion rate. In order to reduce the adverse effect of this microsegregation on plasticity, the microstructure evolution of the Ti-46Al-0.5W-0.5Si alloy homogenized at different temperatures from 1,200 ¡æ to 1,320 ¡æ was investigated, and the optimized process of homogenizing treatment, i.e., annealing treated at 1,280 ¡æ and held for 8 h, was determined. Microstructures of both the as-cast and heat treated alloys were observed by means of optical microscope and scanning electron microscopes. Tensile tests at room temperature were conducted on the homogenizing treated fully lamellar Ti-46Al-0.5W-0.5Si alloy with loading axis parallel to the lamellar interface. Results show that, at higher heat treatment temperatures, the W element diffuses sufficiently, the microstructure tends to be more homogeneous, and the profile of the silicide clusters becomes smooth. Heat treating conducted in the ¦Á+¦Ã two phase region can keep the columnar grains and the original lamellar orientation within them. The microstructure of the alloy after heat treated in ¦Á+¦Ã two phase region exhibits the coexisting morphology of coarse lamellar and thin lamellar. The homogenization process at 1,280 ¡æ for 8 h can significantly reduce the microsegregation, and the elongation at room temperature can increase from 0.48% (as-cast) to 1.34%.
%K ¦Ã-TiAl alloy
%K microsegregation
%K homogenizing treatment
%K fully lamellar
%K plasticity
%U http://www.foundryworld.com/uploadfile/2013040330524855.pdf