Directed energy deposition of PH 13–8 Mo stainless steel: microstructure and mechanical property analysis


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KAŞ M., Muslim T., YILMAZ O., Karagoz T., TÜREDİ E., GÜMÜŞ S., ...Daha Fazla

International Journal of Advanced Manufacturing Technology, cilt.132, sa.1-2, ss.701-715, 2024 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 132 Sayı: 1-2
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1007/s00170-024-13411-3
  • Dergi Adı: International Journal of Advanced Manufacturing Technology
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, IBZ Online, Compendex, INSPEC, DIALNET
  • Sayfa Sayıları: ss.701-715
  • Anahtar Kelimeler: Additive manufacturing (AM), Laser metal deposition (LMD), Mechanical properties, Microstructure, PH 13–8 Mo stainless steel
  • Gazi Üniversitesi Adresli: Evet

Özet

Laser metal deposition (LMD) is of the directed energy deposition (DED) process which is widely used for producing large-scale, dense, and functional parts in the field of additive manufacturing (AM). This research work investigates the microstructure and mechanical properties of PH 13–8 Mo martensitic stainless-steel parts produced via LMD. The workshop trials were conducted using an LMD system collaborated with a robotic arm to deposit single-track thin walls and horizontal blocks. The microstructural characteristics of the additively manufactured parts were analyzed using an optical microscope. The mechanical properties were evaluated through hardness measurements and uniaxial tensile tests. The influence of energy density and powder deposition density on the characteristic geometry of straight walls was also investigated. The microstructural analysis showed that the microstructure consisted of columnar dendrites that grew epitaxially from the substrate, with primary austenite cells containing intercellular ferrite and martensite laths that were roughly parallel with the retained austenite. When the energy density increased from 43 to 86 J/mm2 (a doubling of energy density), there was an increase in secondary dendritic arm spacing (SDAS) by approximately 250% in the first layer and approximately 90% in the top layer. The difference in SDAS change between the first and top layers can be attributed to the difference in cooling rates experienced by each layer during the additive manufacturing process. Increasing powder deposition density from 0.5 to 1 g/min results in a decrease in porosity from 3% to less than 1% and an increase in strength from 800 to over 1000 MPa. The hardness of the deposits was found to range from 300 to 400 HV. This variation in hardness can be attributed to differences in microstructure resulting from changes in cooling rates at different heights.