In-situ microstructural observation of Ti-Cu alloys for semi-solid processing

Autor(es)

Campo, Kaio Niitsu ^{[1, 2]} ; de Freitas, Cabo Chausse ^[1] ; Moon, Suk-Chun ^[2] ; Dippenaar, Rian ^[2] ; Caram, Rubens ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Sch Mech Engn, Campinas, SP - Brazil

^[2] Univ Wollongong, Sch Mech Mat Mechatron & Biomed Engn, Wollongong, NSW - Australia

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS CHARACTERIZATION; v. 145, p. 10-19, NOV 2018.
• Citações Web of Science: 1

Resumo

The semi-solid processing of metallic alloys strongly depends on the microstructural features exhibited by the raw material. Consequently, many characterization techniques have been used to elucidate semi-solid microstructures. In the present work, high-temperature laser-scanning confocal microscopy (HT-LSCM) was used to characterize Ti-Cu alloys intended for thixoforming. During the reheating stage, this in-situ technique enabled us to observe the Ti-beta grains formed through the reverse eutectoid transformation. Furthermore, the results showed that thermomechanical treatment was primarily responsible for breaking up the dendritic microstructure. The liquid formation and peritectic temperature were easily determined via the HT-LSCM investigation. Prior to the reverse peritectic reaction, which corresponds to the onset of equilibrium melting, we obtained experimental evidence of the melting of non-equilibrium phases that originated via segregation during solidification. Finally, it was possible to qualitatively study the coarsening mechanisms that occurred in the semi-solid state. Irrespective of the alloy composition (liquid fraction), both Ostwald ripening and coalescence occurred during the isothermal heat treatments. Based on the obtained results, HT-LCSM can be considered a valuable technique for the characterization of thixotropic alloys. (AU)

• Processo FAPESP: 13/24786-3 - Tixoconformação de ligas de titânio: aplicação aos sistemas Ti-Cu, Ti-Fe e Ti-Co
• Beneficiário: Kaio Niitsu Campo
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 17/07040-9 - Observação in situ de ligas de Ti no estado semissólido via microscopia confocal de varredura a laser
• Beneficiário: Kaio Niitsu Campo
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado