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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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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]
Total Authors: 7
[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
Total Affiliations: 6
Document type: Journal article
Web of Science Citations: 0

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)

FAPESP's process: 18/23582-9 - Microstructural stability of 316L stainless steel processed via selective laser melting using different scanning strategies
Grantee:Leonardo Shoji Aota
Support type: Scholarships in Brazil - Master
FAPESP's process: 19/19442-0 - Microstructural stability of AISI 316L stainless steel processed by selective laser melting using different scanning strategies
Grantee:Leonardo Shoji Aota
Support type: Scholarships abroad - Research Internship - Master's degree
FAPESP's process: 19/06679-1 - Microstructural characterization of precipitation hardening stainless steels processed by additive manufacturing
Grantee:Kahl Dick Zilnyk
Support type: Regular Research Grants