Autor(es)

Conde, Fabio Faria ; Passos, Joao Gabriel da Cruz ; Calderon-Hernandez, Jose Wilmar ; Sharifi, Saham Sadat ; Buzolin, Ricardo Henrique ; Jardini, Andre ; Oliveira, Marcelo Falcao ; Avila, Julian

• Tipo de documento: Artigo Científico
• Fonte: Journal of Materials Engineering and Performance; v. N/A, p. 16-pg., 2025-10-20.

Resumo

Maraging steels like 18Ni-300 offer high strength and toughness due to a low-carbon martensitic matrix with nanosized intermetallic precipitates. Their weldability makes them ideal for additive manufacturing, particularly laser-based powder bed fusion (L-PBF). While L-PBF enhances tooling durability, components face stress, wear, and corrosion challenges, requiring a deeper understanding of structure-property correlations to optimize performance. This alloy can undergo austenite reversion during intercritical or aging, depending on the time and temperature of heat treatment. The formation of reverted austenite implies a depletion of some chemical elements in the martensite matrix, such as Ni in the maraging steel, which could, in theory, lead to a loss of corrosion resistance. This study investigates the influence of reverted austenite on the mechanical and corrosion properties of 18Ni maraging steel produced by L-PBF. To control the volume fraction of reverted austenite, samples were subjected to intercritical heat treatments at 610 and 650 degrees C for varying durations. While the sample with the highest austenite fraction (30.8%) showed poor toughness, a modest 7.5% volume fraction of finely dispersed austenite was sufficient to significantly enhance fracture toughness, indicating that the austenite's stability and morphology are more critical than its bulk volume. We found a clear inverse correlation between austenite content and corrosion resistance in both NaCl and H2SO4 environments. The corrosion potential (Ecorr) decreased from - 637 mV in the as-built sample (3.0% austenite) to - 684 mV in the sample containing 30.8% austenite. This degradation is attributed to micro-galvanic coupling between the Ni-enriched austenite and the Ni-depleted martensitic matrix. (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: 19/00691-0 - Avaliação microestrutural de partes fabricadas por manufatura aditiva para aplicação aeronáutica
• Beneficiário: Julian Arnaldo Avila Diaz
• Modalidade de apoio: Auxílio à Pesquisa - Regular