151. Microstructure characterization and mechanical behavior of laser additive manufactured ultrahigh-strength AerMet100 steel
- Author
-
Haibo Tang, Huaming Wang, Xu Cheng, A. Li, Xian-zhe Ran, and Dong Liu
- Subjects
010302 applied physics ,Austenite ,Materials science ,Bainite ,Mechanical Engineering ,Metallurgy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Mechanics of Materials ,Ferrite (iron) ,0103 physical sciences ,Ultimate tensile strength ,General Materials Science ,Grain boundary ,Composite material ,0210 nano-technology ,Ductility ,Tensile testing - Abstract
Ultrahigh-strength AerMet100 steel thick plate was fabricated by laser additive manufacturing process. The as-deposited microstructures of the test steel were characterized using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The mechanical properties were then examined using vickers-hardness test and tensile test. Results indicate that the as-deposited microstructures of the steel mainly consist of grain boundary allotriomorphic ferrite (GBA), grain interior irregular proeutectoid ferrite, plate-like upper bainite, needle-like lower bainite and retained austenite, which result in a good strength and some ductility anisotropy. The low deformation compatibility of specimen at the transverse direction (perpendicular to the deposition direction) mainly ascribes to the poor cracking resistance of the prior-austenite columnar grain boundary with coarse GBA phases. Compared to the almost intergranular cracking taken place in the transverse tensile specimen, the fracture mode of the longitudinal tensile specimen is a mixed mode of the predominant transgranular cracking and minor intergranular cracking.
- Published
- 2016