Optimization of the Post-Process Heat Treatment of Inconel 718 Superalloy Fabricated by Laser Powder Bed Fusion Process

Metals

Davood Shahriari¹  Mohammad Jahazi¹  Mohammad Saadati¹  Vladimir Brailovski¹  EslamM. Fayed²  Mamoun Medraj² 

[1] Department of Mechanical Engineering, École de Technologie Supérieure, 1100, Notre-Dame Street West, Montreal, QC H3C 1K3, Canada;Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, 1515 Rue Sainte Catherine West, Montreal, QC H3G 2W1, Canada;

关键词: heat treatment optimization;    additive manufacturing;    laser powder bed fusion;    nickel-based superalloy;    IN718;    high-temperature mechanical properties;   

DOI  :  10.3390/met11010144

来源: DOAJ

【 摘 要 】

In the present study, multi-objective optimization is employed to develop the optimum heat treatments that can achieve both high-mechanical performance and non-distinctive crystallographic texture of 3D printed Inconel 718 (IN718) fabricated by laser powder bed fusion (LPBF). Heat treatments including homogenization at different soaking times (2, 2.5, 3, 3.5 and 4 h) at 1080 °C, followed by a 1 h solution treatment at 980 °C and the standard aging have been employed. 2.5 h is found to be the homogenization treatment threshold after which there is a depletion of hardening precipitate constituents (Nb and Ti) from the γ-matrix. However, a significant number of columnar grains with a high fraction (37.8%) of low-angle grain boundaries (LAGBs) have still been retained after the 2.5 h homogenization treatment. After a 4 h homogenization treatment, a fully recrystallized IN718 with a high fraction of annealing twins (87.1%) is obtained. 2.5 and 4 h homogenization treatments result in tensile properties exceeding those of the wrought IN718 at both RT and 650 °C. However, considering the texture requirements, it is found that the 4 h homogenization treatment offers the optimum treatment, which can be used to produce IN718 components offering a balanced combination of high mechanical properties and adequate microstructural isotropy.

【 授权许可】

Unknown