Impact of Heat‐Treatment‐Induced Microstructural Evolution on the High‐Temperature Wear and Corrosion Resistance of L‐PBF Scalmalloy

ABSTRACT The high‐temperature (HT) tribological and corrosion performance of Scalmalloy produced via laser powder bed fusion (L‐PBF) remains insufficiently uncharacterized despite its growing adoption in many industrial applications. This study examines the impact of post‐heat treatment (325°C for 4 h) on the microstructure, nano‐hardness, room‐temperature (RT) and HT tribological behavior and corrosion resistance of the alloy. Microstructural characterization revealed that heat treatment conserved the bimodal microstructure achieved in the L‐PBF process, while improving the homogenous distribution of coherent Al 3 (Sc,Zr) nanoprecipitates, as evidenced by x‐ray diffraction analysis. The coherent nanoparticles restricted the localized plastic deformation by inhibiting the movement of dislocations, thus enhancing the nano‐hardness. The refined precipitate distribution enhanced the nano‐indentation hardness from 3.50 ± 0.10 to 4.26 ± 0.11 GPa, resulting in an improved wear resistance. During reciprocating sliding, the Post‐Heat‐Treated (PHT) Scalmalloy exhibited lower friction coefficient, wear volume loss, and specific wear rate compared to that of As‐Printed (ASP) alloy. With 200°C test temperature, the wear rate was dropped to 39.23%, which was due to the precipitation of Al 3 (Sc,Zr) and the formation of an oxide tribo‐layer. Corrosion resistance was also superior, with the PHT specimen achieving a corrosion rate of 0.3809 mpy at RT and lower weight loss under HT corrosion compared to the ASP condition.