Renato Baldan, Sa˜o Paulo State University (Unesp), Campus of Itapeva, Rua Geraldo Alckmin 519, Itapeva, Sa˜o Paulo, 18409-010, Brazil Antonio Augusto Arau´jo Pinto da Silva, Instituto de Engenharia Mecaˆnica - IEM, Universidade Federal de Itajuba´ UNIFEI, Avenida BPS 1303, Itajuba´, MG 37500-903, Brazil Carlos Angelo Nunes, Escola de Engenharia de Lorena (EEL), Departamento de Engenharia de Materiais (DEMAR), Universidade de Sa˜o Paulo (USP), Estrada Municipal do Campinho, Lorena, Sa˜o Paulo 12602-810, Brazil Antonio Augusto Couto, Instituto de Pesquisas Energe´ticas e Nucleares (IPEN), Av. A variant alloy, called MAR-M246 (Hf), contains 1.5 wt.% hafnium, which is added as a carbide former and grain boundary strengthener. The MAR-M246 superalloy generally solidifies with a dendritic structure containing carbides and exhibits extensive interdendritic segregation. The density of MAR-M246 superalloy is 8.44 g/cm3 and the melting range is between 13, (Ref 2). This superalloy has been widely employed in rotors of automotive turbochargers and in high-pressure turbo pumps (Ref 1). Introduction The MAR-M246 is a polycrystalline nickel-cobalt-tungsten superalloy developed by Martin Marietta Corporation, which became part of Lockheed Martin Inc. KeywordsĪging, heat-treatment, MAR-M246, microstructure, solution, superalloyġ. However, a significant increasing in the c¢ particles was observed at 980 ☌, evidenced by the large mean size of these particles after 80 h of aging heat-treatment. The mean c¢ size of aged samples at 780 and 880 ☌ for 5, 20 and 80 h did not present significant differences when compared to the solutioned sample. The results have shown that the sample solutioned at 1250 ☌ for 330 min showed a very homogeneous c matrix with carbides and cubic c¢ precipitates uniformly distributed. The c¢ size precipitated in the aged samples was measured and compared with JMatPro simulations. The as-cast and heattreated samples were characterized by SEM/EDS and SEM-FEG. The c¢ solvus, solidus and liquidus temperatures were calculated with the aid of the JMatPro software (Ni database). The aim of this work is to evaluate the microstructure of the MAR-M246 nickel-based superalloy solutioned at 12 ☌ for 330 min and aged at 780, 880 and 980 ☌ for 5, 20 and 80 h. Solution and Aging of MAR-M246 Nickel-Based Superalloy Renato Baldan, Antonio Augusto Arau´jo Pintoda Silva, Carlos Angelo Nunes, Antonio Augusto Couto, Sinara Borborema Gabriel, and Luciano Braga Alkmin (Submitted Jin revised form September 23, 2016) Solution and aging heat-treatments play a key role for the application of the superalloys.
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