Mechanism of Strength and Toughness Regulation of Laser Cladding Coatings Based on Interfacial Composite Textures

Abstract

Laser cladding coatings typically exhibit high strength and wear resistance but limited toughness and ductility. To address this, a composite interface texture inspired by biological tissue was developed, using laser cladding to apply Fe-based coatings onto a 1045 steel substrate. The study evaluated the mechanical properties of these coatings, focusing on how varying the depth of the micro-texture impacts performance. Findings revealed that increased micro-texture depth enhanced the bonding strength and coordinated deformation between the coating and substrate. However, it also led to greater stress concentration, increased defect quantity, and higher martensite content at the interface, causing complex shifts in impact toughness, tensile strength, and ductility. A competitive relationship was identified between the coordinated deformation induced by the micro-texture and the stress concentration at the interface. Optimal results were achieved with a micro-texture depth of 0.2 mm, which significantly improved microhardness, tensile strength, and elongation through a synergistic effect, offering the best overall mechanical properties among the tested parameters. This study provides a novel approach to resolving the trade-off between high strength and high toughness in laser cladding coatings. The insights gained are valuable for enhancing the adaptability of these coatings under challenging conditions, such as impact-sliding wear, and shed light on the mechanisms behind the simultaneous improvement in toughness and strength.