Microstructural characterization of 15-5PH stainless steel processed by laser powder-bed fusion

Autor(es)

Unti, L. F. Kultz ^[1] ; Aota, L. S. ^{[2, 3]} ; Jardini, A. L. ^[4] ; Tschiptschin, A. P. ^[5] ; Sandim, H. R. Z. ^[3] ; Jaegle, E. A. ^[6] ; Zilnyk, K. D. ^[1]

Afiliação do(s) autor(es)

^[1] Inst Tecnol Aeronaut, Div Engn Mecan, BR-12228900 Sao Jose Dos Campos, SP - Brazil

^[2] Max Planck Inst Eisenforsch GmbH, D-40237 Dusseldorf - Germany

^[3] Univ Sao Paulo, Lorena Sch Engn, Dept Mat Engn, BR-12602810 Lorena, SP - Brazil

^[4] Univ Estadual Campinas, Inst Biofabricacao, BR-13083970 Campinas, SP - Brazil

^[5] Univ Sao Paulo, Escola Politecn, Dept Engn Met & Mat, BR-05508010 Sao Paulo, SP - Brazil

^[6] Univ Bundeswehr Munchen, Inst Mat Sci, D-85577 Neubiberg - Germany

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS CHARACTERIZATION; v. 181, NOV 2021.
• Citações Web of Science: 0

Resumo

The 15-5PH (UNS S 15500) stainless steel combines high mechanical strength, ductility, and good corrosion resistance for aircraft and aerospace applications. This set of properties and its high added-value applications make it an excellent choice for additive manufacturing processes such as laser powder-bed fusion (LPBF). However, there is a need to understand the complex microstructure developed in LPBF-processed parts, which may show particularities such as columnar solidification, preferential orientation, different kinds of porosities, chemical segregation along the melt pools, metastable phases, and oxide nanoinclusions. We report the micro-structural characterization of LPBF-processed 15-5PH stainless steel in the as-built condition and after aging. Low porosity (<1%), high hardness (420 HV0.1), and a large amount of retained austenite (15%) were found in the as-built samples. The microstructure shows the usual ``fish scale{''}-like morphology. Grain size and hardness vary depending on the location within the melt pools. Reconstruction of the parent grains from EBSD maps indicates a microstructural refinement due to in situ reaustenitization of parts of the previous consolidated layers, where these heat-affected zones are harder and present larger amounts of retained austenite. After aging, as-built samples were harder and more resistant to overaging than annealed or wrought counterparts. Transmission electron microscopy reveals a large amount of nanometric crystalline silicon-oxide inclusions, indexed as cris-tobalite. The combination of fine-grained martensite, coherent Cu-rich clusters, nanometric oxide particles, and retained austenite makes LPBF-processed 15-5PH stainless steel a very promising material for high-end structural applications. (AU)

• Processo FAPESP: 18/23582-9 - Avaliação da estabilidade microestrutural do aço inoxidável austenítico AISI 316L processado via fusão seletiva a laser com diferentes estratégias de escaneamento
• Beneficiário: Leonardo Shoji Aota
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 19/19442-0 - Avaliação da estabilidade microestrutural do aço inoxidável austenítico AISI 316L processado via fusão seletiva a laser com diferentes estratégias de escaneamento
• Beneficiário: Leonardo Shoji Aota
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
• Processo FAPESP: 19/06679-1 - Caracterização microestrutural de aços inoxidáveis endurecíveis por precipitação processados por manufatura aditiva
• Beneficiário: Kahl Dick Zilnyk
• Modalidade de apoio: Auxílio à Pesquisa - Regular