High-temperature oxidation behavior and corrosion resistance of in-situ TiC and Mo reinforced AlCoCrFeNi-based high entropy alloy coatings by laser cladding
“…Taking into account the variety of types of solid solutions that can be created, theoretically, HEA-type materials can have absolutely any properties [ 16 , 17 ]. HEAs based on Ni, Fe, Cr and Mn were found to have high corrosion resistance [ 15 , 18 ], while ceramic phase additions, such as TiC, can further raise the corrosion resistance of HEA-based coatings [ 19 ]. Nickel-based HEAs have a stable strength and hardness at high temperatures [ 15 ], and their wear resistance and strength can be further increased with ceramics such as WC [ 20 ].…”
High-entropy alloys (HEAs) have prospects for use as nuclear structural materials. Helium irradiation can form bubbles deteriorating the structure of structural materials. The structure and composition of NiCoFeCr and NiCoFeCrMn HEAs formed by arc melting and irradiated with low-energy 40 keV He2+ ions and a fluence of 2 × 1017 cm−2 have been studied. Helium irradiation of two HEAs does not change the elemental and phase composition, and does not erode the surface. Irradiation of NiCoFeCr and NiCoFeCrMn with a fluence of 5 × 1016 cm−2 forms compressive stresses (−90 … −160 MPa) and the stresses grow over −650 MPa as fluence increases to 2 × 1017 cm−2. Compressive microstresses grow up to 2.7 GPa at a fluence of 5 × 1016 cm−2, and up to 6.8 GPa at 2 × 1017 cm−2. The dislocation density rises by a factor of 5–12 for a fluence of 5 × 1016 cm−2, and by 30–60 for a fluence of 2 × 1017 cm−2. Stresses and dislocation density in the HEAs change the most in the region of the maximal damage dose. NiCoFeCrMn has higher macro- and microstresses, dislocation density, and a larger increase in their values, with an increasing helium ion fluence compared to NiCoFeCr. NiCoFeCrMn a showed higher radiation resistance compared to NiCoFeCr.
“…Taking into account the variety of types of solid solutions that can be created, theoretically, HEA-type materials can have absolutely any properties [ 16 , 17 ]. HEAs based on Ni, Fe, Cr and Mn were found to have high corrosion resistance [ 15 , 18 ], while ceramic phase additions, such as TiC, can further raise the corrosion resistance of HEA-based coatings [ 19 ]. Nickel-based HEAs have a stable strength and hardness at high temperatures [ 15 ], and their wear resistance and strength can be further increased with ceramics such as WC [ 20 ].…”
High-entropy alloys (HEAs) have prospects for use as nuclear structural materials. Helium irradiation can form bubbles deteriorating the structure of structural materials. The structure and composition of NiCoFeCr and NiCoFeCrMn HEAs formed by arc melting and irradiated with low-energy 40 keV He2+ ions and a fluence of 2 × 1017 cm−2 have been studied. Helium irradiation of two HEAs does not change the elemental and phase composition, and does not erode the surface. Irradiation of NiCoFeCr and NiCoFeCrMn with a fluence of 5 × 1016 cm−2 forms compressive stresses (−90 … −160 MPa) and the stresses grow over −650 MPa as fluence increases to 2 × 1017 cm−2. Compressive microstresses grow up to 2.7 GPa at a fluence of 5 × 1016 cm−2, and up to 6.8 GPa at 2 × 1017 cm−2. The dislocation density rises by a factor of 5–12 for a fluence of 5 × 1016 cm−2, and by 30–60 for a fluence of 2 × 1017 cm−2. Stresses and dislocation density in the HEAs change the most in the region of the maximal damage dose. NiCoFeCrMn has higher macro- and microstresses, dislocation density, and a larger increase in their values, with an increasing helium ion fluence compared to NiCoFeCr. NiCoFeCrMn a showed higher radiation resistance compared to NiCoFeCr.
“…As we know, Ecorr and Icorr are important parameters of corrosion resistance. In general, the stronger the corrosion resistance, the higher E corr value, and the lower the corrosion thermodynamic tendency is; I corr is the corrosion current, which reflects the generation speed of metal ions and is closely related to the corrosion rate [ [35] , [36] , [37] ]. From Table 4 , we can understand that the values of I corr are very close to each other when x is 2 %, 4 % and 6 %, so for this experiment we use E corr to determine the superiority of corrosion resistance.…”
Section: Resultsmentioning
confidence: 99%
“…As above, WC particles have obvious influence on the microstructure of the coating.When the WC ratio is 2 %, both spicate-like crystals and cellular crystals can be found in the coating. And the special structure is contributed to the enhancement of corrosion performance [ 38 , 39 ]. Fig.…”
“…In addition, as the TiC and TiB2 contents increased, the microhardness of the cladding layer was refined, which had a positive effect on the microhardness and strengthening of the ceramic phase. At the same time, the uniform distribution of TiC and TiB2 phases hindered the movement of dislocations, which promoted the uniform dispersion strengthening [37,38].…”
Section: Phase Composition and Microstructurementioning
Four metal-ceramic composite coatings were prepared by laser cladding (LC) using Hastelloy C-276, nano-TiC and micro-TiB2 as raw materials to improve the surface properties and extend the service life of 316L stainless steel. The microstructure and mechanical properties were analyzed by metallographic microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers hardness experiments, and friction and wear testing. The TiC and TiB2 phases were detected in the coating, exhibiting homogenous distribution as their content increased. As a result, the strengthening effect of the coating was enhanced, improving microhardness relative to that of the 316L substrate. The wear test revealed that the Hastelloy coating exhibited poor wear resistance, but the addition of TiC and TiB2 particles improved the wear resistance by reducing the wear rate. The lowest average coefficient and wear rate were attained at 50% and 70% ceramic contents, respectively. However, abundant hard particles on the surface easily fell off during the wear, which further impeded the surface degradation and increased the friction coefficient.
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