Direct Observation of Austenite Reversion During Aging of 18Ni (350 Grade) Maraging Steel Through In-Situ Synchrotron X-Ray Diffraction

Autor(es)

Melo Feitosa, Ana Larissa ^[1] ; Escobar, Julian ^[1] ; Ribamar, Giovani Goncalves ^[1] ; Avila, Julian Arnaldo ^[2] ; Padilha, Angelo Fernando ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Met & Mat Engn, Av Prof Mello Moraes 2463, BR-05508030 Sao Paulo, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Campus Sao Joao da Boa Vista, BR-13876750 Sao Joao Da Boa Vista, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE; v. 53, n. 2 NOV 2021.
• Citações Web of Science: 0

Resumo

Austenite reversion in Fe-Ni alloys plays a significant role in determining their mechanical properties. Increasing the austenite content in these alloys improves their toughness but reduces their mechanical strength. In this work, austenite-reversion heat treatments between 600 degrees C and 700 degrees C were studied in-situ using synchrotron X-ray diffraction and scanning electron microscopy (SEM) in an 18Ni (350) maraging steel. Aging heat treatments were simulated in three steps: slow heating (0.666 degrees C s(-1)), soaking for 1 hour at temperatures between 600 degrees C and 700 degrees C, and cooling with forced Ar. After the treatments, the samples were prepared for SEM and microhardness analyses. The reverted austenite fraction increases with the aging temperature, and this phase proved to be partially unstable after aging at a temperature above 675 degrees C, and it is transforming partially to martensite after cooling. In addition to the increase in the reverted austenite fraction, the coalescence and dissolution of precipitates occurred simultaneously and decreased the hardness. (AU)

• Processo FAPESP: 17/17697-5 - Avaliação mecânica e microestrutural de peças fabricadas por manufatura aditiva no aço 18%Ni Maraging 300 com aplicação aeronáutica.
• Beneficiário: Julian Arnaldo Avila Diaz
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/21251-5 - Caraterização do efeito de endurecimento secundário ativado por temperatura de aços resistentes ao fogo durante a simulação de incêndios
• Beneficiário: Julian David Escobar Atehortua
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado