Crack Formation Mechanisms and Control Methods of Laser Cladding Coatings: A Review

Abstract

Laser cladding, a novel surface treatment technology, utilizes a high-energy laser beam to melt diverse alloy compositions and form a specialized alloy-cladding layer on the surface of the substrate to enhance its property. However, it can generate substantial residual stresses during the rapid cooling and heating stages, due to inadequate selection of cladding process parameters and disparities in thermophysical properties between the clad layer and substrate material, leading to the formation of various types of cracks. These cracks can significantly impact the quality and performance of the coating. This paper presents a comprehensive review of crack types and their causes in laser cladding coatings, and identifies that three primary sources of residual stresses, thermal stress, organizational stress, and restraint stress, are the fundamental causes of crack formation. The study proposes several strategies to control coating cracks, including optimizing the coating layer material, refining the coating process parameters, incorporating heat treatment, applying auxiliary fields, and utilizing numerical simulations to predict crack initiation and propagation. Additionally, the paper summarizes crack control methods for emerging structural materials and novel preparation processes. Lastly, the paper analyzes the prospects, technical approaches, and key research directions for effectively controlling cracks in laser cladding coatings.

Fabrication of Smart Materials Using Laser Processing: Analysis and Prospects

“…Cladding, on the other hand, revolves around the application of a layer of one material onto the surface of another, thereby modifying its characteristics [52,101,102]. It is worth noting that the improper selection of cladding process parameters and the mismatch of thermophysical properties between the cladded layer and the substrate material can lead to the development of substantial residual stresses during rapid cooling and heating phases, potentially resulting in various types of cracks [103]. In [104], NiCrSiBC-WC composite coatings were studied with different WC mass ratios on carbon steel substrates, revealing that 40 wt.% WC coatings were crack-free, while those with 50% and 60% WC displayed cracks (Figure 6a).…”

Effects of Process Parameters on Microstructure and Wear Resistance of Laser Cladding A-100 Ultra-High-Strength Steel Coatings

“…To reduce the cracking tendency of cladding coatings, it is necessary to reduce their residual stress. In the process of laser cladding, the solidification rate of the molten pool is related to the magnitude of residual stress and closely related to the parameters of the laser cladding process [15]. Therefore, optimizing the cladding coating manufacturing process parameters is beneficial to reducing the residual stress of the cladding coating.…”

Effect of Minor Mo Addition on Microstructure and Corrosion Resistance of High-Velocity Air Fuel-Sprayed Fe-Based Amorphous Coatings

“…Irrespective of the limitations of glass-forming ability (GFA), amorphous alloys fabricated as protective coatings instead of bulk show great application prospects [6][7][8]. Currently, the major techniques for preparing Fe-based amorphous coatings are thermal spraying and laser cladding [9][10][11]. Fe-based amorphous coatings prepared by laser cladding have fewer holes and the coating size can be precisely controlled.…”

“…Fe-based amorphous coatings prepared by laser cladding have fewer holes and the coating size can be precisely controlled. However, due to the high laser energy, most of the prepared coatings have crystalline phases and crack [11,12]. In comparison, the high-velocity air fuel (HVAF) thermal spraying technique, which provides the advantages of high flight of sprayed particles and large kinetic energy, is widely used in the creation of Fe-based amorphous coatings [13][14][15].…”