Interfacial Properties of Additively Manufactured M789 Steel on Wrought N709 Alloy

Abstract

An additively manufactured M789 steel was deposited on wrought precipitation-hardening N709 steel to form a hybrid alloy using the laser powder bed fusion (LPBF) process. After tensile testing, failure in the as-printed (AP) state was detected in the M789 section with a peak strength of 1019 MPa, consistent with the nanoindentation measurement across the M789-N709 interface. The application of heat treatment of the hybrid alloy shifted the failure zone to the N709 alloy with a peak strength of 1600 MPa. The high strength of M789 after heat treatment was due to the formation of the η-phase during aging. A robust metallurgical bond was successfully formed between the two alloys since the fracture did not occur in the interface for both the AP and heat treated (HT) states during tensile testing.

Themomechanical Response of an Additively Manufactured Hybrid Alloy by Means of Powder Bed Fusion

“…The hybrid material was manufactured by printing M789 steel on top of N709 steel using an EOS M290 L-PBF machine at voestalpine Additive Manufacturing Center (vAMC) in Mississauga, Ontario, Canada. The composition of the materials is presented in Table 1, while the laser printing parameters are available in Refs [12][13]. Since the focus of the work is the high-temperature response of individual materials, small cylindrical samples, with diamaters and heights of 6 mm and 9 mm, respectively, were machined from the manufactured part, with the length of the sample parallel to the building direction.…”

“…Currently, this hybrid technique is employed in the manufacturing of tool and die molds, where the complex conformal cooling channels are printed on top of conventionally fabricated substrates. For example, the present authors conducted a study on the printing of M789 steel on top of N709 steel to create a hybrid material [12][13]. Their work demonstrated that the bonding between M789 and N709 is stronger than the strength of the individual base materials, making it suitable for tool and die mold applications.…”

“…Therefore, this work aims to address the need for hightemperature mechanical response of hybrid additive manufacturing. The researchers conducted individual tests on two materials: i) LPBF-produced M789 steel and ii) wrought N709 steel, based on their previous work on hybrid additive manufacturing [12][13]. The established material models in this study, which are not available in the literature, can be utilized to generate accurate finite element simulations for components subjected to elevated temperature applications.…”