Study on crack behavior of laser cladding ceramic-metal composite coating with high content of WC

Predicting the CTE & hardness for directed energy deposition of functionally graded WC-SS316L Coatings

“…Hence, it is important to determine a compositional window at which the CTE difference between successive layers is reduced. Previous studies have found that material combinations with little or no CTE mismatch demonstrate the least interfacial cracks [6,7,21].…”

“…This is especially true in DED due to the localized heating and cooling which leads to non-uniform thermal expansion and contraction. This results in structural defects such as distortions, warping, cracks, and delamination [6]. Such cracks affect the structural performance of the coating and should be minimised.…”

“…These cracks were found to propagate along eutectic phases showing high brittleness. Shen [6] studied the effect of increasing wt.% WC in a NiCrSiBC composite coating deposited onto carbon steel substrates using laser cladding. It was observed that as the wt.% WC increased, the degree of cracking increased.…”

“…The issues encountered can be attributed to dissimilarities in the material and metallurgical properties of the constituent materials. These differences can be accounted for as 1) solidification cracking, which occurs as a result of the large solidification range between WC and the binder material [8]; 2) chemical incompatibilities that prevent perfect mixing or the formation of brittle intermetallic phases [9]; and 3) high internal stresses generated from the mismatch in the coefficient of thermal expansion and these can lead to macro/microscopic cracking [6,7].…”

Ultrasonic-Induced Grain Refinement in Laser Cladding Nickel-Based Superalloy Reinforced by WC Particles

“…Xia et al [14] studied the tribological properties of laser melting GH3536-WC composite coatings reinforced by coarse and fine WC particles, concluding that the more uniform distribution of fine WC particles can significantly enhance the effect of dispersion strengthening under the same WC content. Shen et al [15] fabricated NiCrSiBC-WC composite coatings with different WC content to investigate the mechanism of grain refinement and crack behavior, and found that high WC content can refine solidified structures obviously while also causing increases in the tensile stress and crack susceptibility of coatings. In fact, due to the differences in physical properties between ceramic particles and Ni-based alloy as well as the rapid melting/solidification characteristics of laser cladding, metallurgical defects such as uneven distribution of WC ceramic particles, cracks and pores are more likely to appear in the composite coating [16][17][18].…”