To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm ...To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm × 2 mm was obtained. The microstructure of stip casting sheets and heat treatments was systematically studied. The macrostructure consisted of columnar crystals extending inward and centrally located equiaxed crystals with severe Al segregation were observed along the thickness direction, due to the symmetrical solidification process and decreasing cooling rates. The strip casting alloy was characterized by fine duplex microstructure with a grain spacing of 20-30 μm and a lamellar spacing of 10-20 nm. Furthermore, multiple microstructures of near gamma, nearly lamellar and fully lamellar were obtained through heat treatment process with significantly improved homogeneity of the microstructure.展开更多
基金Project(51504060) supported by the National Natural Science Foundation of ChinaProjects(2016YFB0301201,2016YFB0300603) supported by the National Key Research and Development Program of ChinaProject(N160713001) supported by the Fundamental Research Funds for the Central Universities,China
文摘To shorten the fabrication process of difficult-to-form TiAl sheets, twin-roll strip casting and microstructural control were investigated in Ti-43Al alloy. A crack-free sheet with dimensions of 1000 mm × 110 mm × 2 mm was obtained. The microstructure of stip casting sheets and heat treatments was systematically studied. The macrostructure consisted of columnar crystals extending inward and centrally located equiaxed crystals with severe Al segregation were observed along the thickness direction, due to the symmetrical solidification process and decreasing cooling rates. The strip casting alloy was characterized by fine duplex microstructure with a grain spacing of 20-30 μm and a lamellar spacing of 10-20 nm. Furthermore, multiple microstructures of near gamma, nearly lamellar and fully lamellar were obtained through heat treatment process with significantly improved homogeneity of the microstructure.
