Tensile Ductility of Cast TiAl Alloys

Abstract

The microstructural characteristics and room temperature tensile ductility in some cast TiAl alloys were analyzed. It was found that grain refinement, either through Q&A treatment in boron-free alloys or through low dose of boron addition in beta solidifying alloys with lamellar microstructures, is not sufficient for good ductility. For cast alloys with convoluted microstructures and fine lamellar microstructures the orientation distribution of gamma grains/lamellar colonies plays an important role in controlling ductility. In those fine-grained alloys a highly random orientation distribution of gamma grains/lamellar colonies is essential to improvement in ductility.