Tribological Behavior and Wear Mechanism of Selective Laser Melted Inconel 718: Influence of Scanning Strategies and Heat Treatment

Abstract

Abstract. This study investigates the effect of three different types of scanning strategies (0 deg rotation, 67 deg rotation, and chessboard) on microhardness and wear properties of selective laser-melted Inconel 718 samples. Additionally, it explores in detail how heat treatment enhances wear properties across all the scanning strategies. The wear response of the as-built specimens was strongly influenced by their hardness and the microstructural characteristics imparted by different scanning strategies. The chessboard scanning strategy demonstrated the highest microhardness and wear resistance (lowest coefficient of friction (COF) of ∼0.53, wear volume of ∼0.134 mm3), whereas the 0 deg rotation showed the least (highest COF of ∼0.57, wear volume of ∼0.184 mm3). Wear resistance of 67 deg rotation (COF of ∼0.55, reduced wear volume of ∼0.163 mm3) lies between the 0 deg rotation and the chessboard scanning strategy. Adhesive wear dominated in the 0 deg rotation strategy, while abrasive wear was prevalent in the chessboard pattern; the 67 deg rotation showed mainly abrasive wear with reduced adhesive wear mechanism. Heat treatment improved the wear resistance of all samples by enhancing microhardness and promoting the transformation of columnar grains into equiaxed ones, where the increased grain boundary density acted as an effective barrier to dislocation motion. After heat treatment, the 0 deg rotation sample showed the highest COF (∼0.52) and wear volume (∼0.150 mm3) followed by the 67 deg rotation (∼0.50, ∼0.124 mm3), while the chessboard strategy showed the lowest COF (∼0.47) and wear volume (∼0.108 mm3). Heat-treated 67 deg rotation sample showed the highest improvement, with a 26.71% increase in hardness and a 23.9% gain in wear resistance.