Microstructure and Mechanical Behavior of 17-4 Precipitation Hardenable Steel Processed by Selective Laser Melting

• Published in: Journal of materials engineering and performance Vol. 23; no. 12; pp. 4421 - 4428
• Main Authors: Rafi, H. Khalid, Pal, Deepankar, Patil, Nachiket, Starr, Thomas L., Stucker, Brent E.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-12-2014; Springer
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Cross-disciplinary physics: materials science; rheology; Elasticity. Plasticity; Engineering Design; Exact sciences and technology; Martensitic transformations; Materials Science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Quality Control; Reliability; Safety and Risk; Tribology; microstructure formation; selective laser melting; austenite-to-martensite phase transformation; Grain size; Heat treatment; Stress strain relation; Tensile property; Phase analysis; Controlled atmosphere; Precipitation hardening; Columnar structure; Retained austenite; Selective laser melting; Stainless steel; Martensitic transformation; Microstructure; Martensite
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-014-1226-y

The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical microscopy, scanning electron microscopy, and x-ray diffraction. The results show that post-process heat treatment is required to obtain typically desired tensile properties. Columnar grains of smaller diameters (<2 µm) emerged within the melt pool with a mixture of martensite and retained austenite phases. It was found that the phase content of the samples is greatly influenced by the powder chemistry, processing environment, and grain diameter.