Effects of hot isostatic pressing treatment on the microstructure and tensile properties of Ni-based superalloy CM247LC manufactured by selective laser melting

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2022-04, Vol.841, p.143083, Article 143083
• Main Authors: Lee, Jung-Uk, Kim, Young-Kyun, Seo, Seong-Moon, Lee, Kee-Ahn
• Format: Article
• Language: English
• Subjects: Deformation mechanisms; Elongation; Grains; Heat treating; Hot isostatic pressing; Laser beam melting; Lasers; Mechanical properties; Microstructure; Ni-based superalloy; Nickel base alloys; Powder beds; Processing optimization; Rapid prototyping; Selective laser melting; Superalloys; Tensile properties; Tensile property; Tensile strength; Yield strength; Yield stress
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.143083

This study manufactured CM247LC Ni-based superalloy, which has outstanding mechanical properties, using the laser powder bed fusion (L-PBF) method and selective laser melting (SLM). Furthermore, the effect of hot isostatic pressing (HIP) post treatment on the microstructure and mechanical properties of SLM-built CM247LC was investigated. The defect characteristics of SLM-built superalloy changed significantly according to scan speed and hatch space, and it achieved the optimal microstructure at an intermediate scan speed (600 mm/s). SEM, EBSD, and ECCI analyses of the as-built alloy identified grains that developed in the build direction, sub-grains consisting of dislocation networks and MC carbides. In addition, γ’ phase formed evenly throughout the sample after HIP post treatment. The as-built CM247LC showed a yield strength of 933.5 MPa and tensile strength of 1144.0 MPa. In the case of the HIP alloy, the yield strength remained at a similar level, but tensile strength increased significantly up to 1457.1 MPa, and tensile elongation increased four times compared to the as-built alloy. Based on the above findings, this study discussed the correlations between microstructure, improved tensile properties and deformation mechanism. •Ni-based superalloy CM247LC alloy was manufactured using selective laser melting process.•Defects, microstructure and mechanical properties were controlled through hot isostatic pressing post-treatment.•HIPed SLM-built CM247LC alloy showed high tensile strength and elongation.•The shape and volume fraction of MC carbide in CM247LC alloy affects the elongation.