Experimental investigation into microstructure, mechanical properties, and cracking mechanism of IN713LC processed by laser powder bed fusion

IN713LC is a Ni-based superalloy with extensive uses in the aerospace industry. However, fabricating IN713LC components using additive manufacturing technologies such as laser powder bed fusion (LPBF) is extremely challenging due to its high composition of alloying elements (e.g., Al and Ti), which increase its susceptibility to cracking. Accordingly, the present study conducts an experimental investigation into the LPBF processing parameters (i.e., laser power and scanning speed) which enable the fabrication of LPBF IN713LC parts with a high relative density and minimal cracking. The effects of heat treatment on the microstructure and mechanical properties of the as-built parts are then examined. The results show that IN713LC is prone to the two microcracking mechanisms, namely solidification cracking due to the formation of low-melting-point elements at the grain boundaries and ductility dip cracking (DDC) as a result of grain boundary sliding. However, given an appropriate selection of the LPBF processing conditions, as-built IN713LC components with an average yield strength of 800 MPa, an ultimate tensile strength of 998 MPa, and ultimate elongation of 12.5% at room temperature are better than those of as-cast IN713LC specimens. Notably, the solid solution heat treatment process yields a significant improvement in the yield strength compared to that of the as-built sample. Moreover, all the mechanical properties of the sample processed by solid solution heat treatment are comparable to those of the ascast IN713LC sample.

Automated summary

IN713LC, a Ni-based superalloy, poses challenges in LPBF manufacturing due to its high susceptibility to cracking, with study revealing the importance of LPBF processing parameters and solid solution heat treatment in improving mechanical properties.