As-cast titanium aluminides microstructure modification



Título del documento: As-cast titanium aluminides microstructure modification
Revista: Materials research
Base de datos: PERIÓDICA
Número de sistema: 000312394
ISSN: 1516-1439
Autores: 1

Instituciones: 1Universidade do Porto, Departamento de Engenharia Metalurgica e de Materiais, Porto. Brasil
Año:
Periodo: Jul
Volumen: 2
Número: 3
Paginación: 191-195
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental
Resumen en inglés Two cast g titanium aluminides, Ti47Al and Ti50Al (at. %), were obtained by arc melting under an argon atmosphere. The as-cast microstructure modification by annealing under protective argon atmosphere and hot isostatic pressing (HIP) was analysed by optical and scanning electron microscopy with microanalysis facilities. As-cast structures presented strong microsegregations, being composed of primary a dendrites (with low Al content), which transformed into lamellar a2 + g during solid state cooling, and interdendritic g phase (with high Al content). Annealing in the a + g field was responsible for a partial reduction of microsegregation, a decreasing of the volume fraction of a2 + g lamellar dendrites, an increasing of g volume fraction and the occurrence of a small fraction of a2 particles and plates in some of the g grains. Annealing in the a field at 1400 °C for one hour was insufficient to eliminate the as-cast microstructure in the Ti50Al alloy and produced large equiaxed lamellar colonies of a2+g in the Ti47Al alloy. HIP in the a + g field (to avoid excessive grain growth) was responsible for microstructure modifications similar to the ones obtained by heat treating under similar soaking conditions
Disciplinas: Ingeniería
Palabras clave: Ingeniería de control,
Ingeniería química,
Microestructuras,
Titanio,
Tratamiento térmico
Keyword: Engineering,
Chemical engineering,
Control engineering,
Microstructures,
Titanium,
Heat treatment
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