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The bottleneck challenge of laser‐cladded coating preparation of magnesium alloys is the low melting point of alloys. This greatly restricts the selection of coating material. In this article, the composition of Ni–Ti–Cu coating is designed by cluster line criterion, and the thermal properties of the coating are simulated by JMatPro software. Through the analysis of simulation results, the Ni51.6Ti34.4Cu14 coating is selected and successfully prepared on AZ91D magnesium alloy via laser cladding technology. Then the microstructure, wear resistance, and corrosion resistance of the coating are studied in detail. The results of X‐Ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and transmission electron microscope (TEM) demonstrated that there is a good metallurgical bond between the coating and the substrate, and the coating is mainly composed of Ni3Ti, TiNi0.8Cu0.2, and (Cu, Ni) solid solution phases. Also, there are no obvious pores and crack defects in the coating. Remarkably, AZ91D alloy showed significant improvement in corrosion resistance and wear resistance. Among them, the wear volume of the coating is decreased by 71.9% than that of AZ91D alloy. In particular, the corrosion current density of the coating is three orders of magnitude lower than that of AZ91D alloy. [ABSTRACT FROM AUTHOR]

The poor surface properties of Mg Li alloys and the excellent comprehensive performance of high-entropy alloy (HEA) coatings are highly complementary. This study uses laser cladding technology to deposit an AlTiVNiCu/Cu–Al gradient functional coating with favourable wear and corrosion properties on Mg Li alloy substrates. Through the design of the gradient coating structure, laser cladding is used to coat HEA layers on low-melting-point Mg Li alloys, which effectively reduces further dilution of Mg and Li in the substrate. Notably, the Mg content in the prepared AlTiVNiCu protective layer is only 2.34 %. Furthermore, the microstructure, phase structure, microhardness, tribological and corrosion properties of the gradient coating are systematically studied. The protective layer consists of V-rich BCC 1 , (Ni, Ti)-rich BCC 2 , Cu-rich FCC, Mg-rich BCC 3 and nanoscale β -Ti phases, with a predominance of body-centered cubic (BCC) structural phases. The average microhardness is 547.46 HV0.3. Under a load of 3 N, the average friction coefficient of the protective layer is 0.54, with a wear volume of only 2.87 % compared with that of the substrate, which is satisfactory wear resistance. In a 3.5 wt% NaCl solution, the protective layer exhibits the highest corrosion potential (−0.49 V SCE , where SEC denotes saturated calomel electrode), and the lowest corrosion current density (1.14 × 10−6 A·cm−2), representing a remarkable enhancement compared with those of the substrate (−1.57 V SCE and 5.41 × 10−4 A·cm−2). [Display omitted] • Laser-cladded AlTiVNiCu HEA coatings were designed and prepared on Mg Li alloy. • LC-Cu 6 Al layer helps to balance the thermal mismatch between the HEA coating and Mg Li. • HEA coatings consist of V-rich, (Ni, Ti)-rich, Cu-rich, Mg-rich and β-Ti phases. • HEA coatings show good wear resistance with a wear volume of 2.87 % of the substrate. • HEA coatings have higher E corr and lower i corr values for good corrosion resistance. [ABSTRACT FROM AUTHOR]

Aluminum bronze coatings were prepared on MBLS10A-200 magnesium-lithium alloy substrate by cold spraying technology to improve the surface properties of Mg–Li alloys. The microstructure, phase composition, microhardness, tribological properties and corrosion resistance of the coatings were systematically analyzed. The results show that aluminum bronze coatings are mainly composed of α phase. β phase in the original aluminum bronze powder disappeared in the coating due to the eutectoid transition of β→α + γ 2 during the cold spraying. Compared with the Mg–Li alloy substrate, the aluminum bronze coating exhibits the higher microhardness (222.88 HV 0.3) and wear resistance (friction coefficients, wear track widths and wear mass losses are 0.37, 0.79 mm and 2.47 mg, respectively). The dominant wear mechanism of the coatings was abrasive wear. In the electrochemical test, the corrosion current density of the aluminum bronze coating (3.07 × 10−5 A/cm2) was an order of magnitude lower than that of Mg–Li alloy substrate (6.15 × 10−4 A/cm2), indicating that the coating had superior corrosion resistance. The above analysis confirms that preparing a cold sprayed aluminum bronze coating has outstanding tribological and corrosion resistance properties. • Aluminum bronze coatings were prepared on Mg–Li alloy by cold spraying. • Aluminum bronze coatings are mainly composed of α phase. • The eutectoid transformation of β. →α + γ 2 occurred during the cold spraying process. • The wear and corrosion resistance of Mg–Li alloy are comprehensively improved. [ABSTRACT FROM AUTHOR]

The incorporation of Laves phase into HEAs coating represents a novel approach to enhance wear resistance, building upon the innovative background of titanium alloy surface protection. The TiAlZrVNi X (X = 1, 1.5, 2) HEAs coatings were prepared in this study using laser cladding advantages to achieve dependable wear-resistant coatings. The microstructure, phase composition, microhardness, and tribological properties of the HEA coatings were simultaneously investigated. TiAlZrVNi X coatings were composed of V-rich HCP solid solution phases, C14-Laves phases, and NiTi 2 phases. The microhardness of the 1.5Ni coating measured 708.75HV 0.3 and wear rate of 1.12 × 10−13m3N−1 m−1. The primary wear mechanism was abrasive wear, and it had been confirmed that the 1.5Ni coating exhibited best wear resistance. The Laves phase with high space utilization would produce precipitation strengthening and dispersion strengthening, effectively reducing the stress-induced microcrack diffusion. Additionally, the introduction of Ni elements induced the growth of the NiTi 2 phase in order to enhance the strength while mitigating brittleness, thereby enhancing the wear resistance of the coatings. • The TiAlZrVNi X (X = 1, 1.5, 2) HEAs coatings were prepared by laser cladding. • Laves phase was introduced by adding Ni element to improve the properties of the coating. • The Laves phase content was modulated by the NiTi 2 phase. • The wear mechanisms of TiAlZrVNi X coatings displayed with varying Ni content were investigated. [ABSTRACT FROM AUTHOR]

This study proposes the utilization of rare earth combined with ultrasonic-assisted laser cladding technology to address the dilution problem encountered during the laser cladding coating of Ti alloy. The aim is to improve the performance of the coating. Using Ti alloy surface as a base, a novel Ti-Al-Si-Cr-SiC multi-principal element alloy coating is fabricated. To characterize the coating, various techniques such as transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and scanning electron microscopy (SEM) are employed to examine the microstructure and phase composition. The interface between the coating and the substrate is analyzed using focused ion beam and TEM. The coatings are also evaluated for corrosion and wear resistance through potentiodynamic polarization, electrochemical impedance spectroscopy, hardness, and friction tests. The results reveal that the rare earth combined with ultrasonic-assisted Ti-Al-Si-Cr-SiC coating consists of Ti 4 Cr phase, TiC phase, and eutectic phase (Ti 3 Al and Ti 5 Si 3). The combined effect of ultrasonic energy and rare earth reduces the dilution rate of the coating, resulting in a refined coating structure that improves the wear resistance and corrosion resistance. • A new preparation method of ultrasonic composite rare earth assisted laser cladding was proposed. • The dilution rate of the coating prepared by rare earth-ultrasonic assisted laser cladding is significantly reduced. • Microstructure refinement promotes the formation of stable passivation film and improves the corrosion resistance. • The coating prepared by rare earth combined with ultrasonic assisted laser cladding has good wear and corrosion resistance. [ABSTRACT FROM AUTHOR]

Ti-Al-Si-SiC-Cr x (X = 0, 5, 10, 15) coatings were prepared on TC4 alloy by laser cladding, and their microstructure and tribological properties were investigated. The results reveal that the coatings consist of Ti 3 Al, TiC, Ti 5 Si 3 , and Ti 4 Cr phases. In room temperature friction, with the addition of Cr, Ti 4 Cr soft phase was formed in the coating, which reduced the three-body wear of the coating. However, an excess of Ti 4 Cr soft phase induces a reduction in the wear resistance of the coating. Under high temperature friction conditions, due to the addition of Cr, a super-hard amorphous oxide protective layer is formed on the wear surface to improve the wear resistance of the coating. Therefore, Ti-Al-Si-SiC-Cr 10 coating has the best tribological properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-Ti-Cu/Cu-Al functionally graded coating was prepared on Mg-Li alloy by laser cladding. • The graded coating was constructed to solve the problem that the influence of evaporation and dilution about Mg and Li elements on the performance of coating. • Typical hypoeutectic structure composed of Li 3 Mg 7 and CuMg 2 was obtained in the interlayer (Cu-Al). • The corrosion and wear resistance of Mg-Li got huge improvement. The bottleneck challenge of preparing laser cladded coating on Mg-Li alloys is the evaporation and dilution of substrate, which seriously affect the performance of coatings. In order to solve these deficiencies, Ni-Ti-Cu/Cu-Al functionally graded coating was proposed in this work. The graded coating with excellent performance was successfully prepared on Mg-Li alloy. More remarkable, the top-layer was not affected by dilution and substrate evaporation. The top-layer was mainly composed of Ni 3 Ti and NiTi intermetallic compounds, as well as TiNi 0.8 Cu 0.2 phase that dispersed on the surface of Ni 3 Ti. Typical hypoeutectic structure was found in the interlayer, which was composed of Li 3 Mg 7 and CuMg 2. Furthermore, the corrosion and wear resistance of Mg-Li alloy were greatly improved. Specifically, the wear volume of the top-layer and interlayer is reduced by 98.04% and 82.41% than that of substrate, respectively. The corrosion potential of the top-layer (-242 mV) and the interlayer (-991 mV) are 1311 mV and 562 mV higher than that of the substrate (-1553 mV), while the corrosion current density of the top-layer (2.71 × 10-7 A·cm−2) and the interlayer (1.93 × 10-6 A·cm−2) are about three and two orders of magnitude lower than that of the substrate (2.53 × 10-4 A·cm−2). [ABSTRACT FROM AUTHOR]

NiTi 98-x Si x C 2 (x = 0, 4, 8 wt%) coatings were prepared on Ti-6Al-4V substrate by laser cladding to improve the surface mechanical properties of NiTi coatings. The effects of Si content addition on the microstructure, phase composition, microhardness, and tribological properties of the coatings were systematically analyzed. The results show that NiTi 98-x Si x C 2 (x = 0, 4, 8) coatings are mainly composed of NiTi, NiTi 2 , TiC, and Ti 5 Si 3 phases. The rod-like phase of Ti 5 Si 3 was found in NiTi 90 Si 8 C 2 coating, while the rod-like phases were found broken. The fragmentation of the rod-like phase is related to the growth of the NiTi phase around it. At the same time, TEM results show that the NiTi (B2) phase and Ti 2 Si second phase are exited in the NiTi 90 Si 8 C 2 coating. Ti 2 Si, which has not been decomposed into Ti 5 Si 3 , remains during the laser cladding process. In addition, the eutectic structure in NiTi 90 Si 8 C 2 coating was observed in some regions. The average microhardness of the NiTi 98-x Si x C 2 (x = 0, 4, 8) coating were at 534.08 HV 0.5 , 598.06 HV 0.5 , and 974.08 HV 0.5 , respectively. The wear resistance of NiTi 98-x Si x C 2 (x = 0, 4, 8) coatings increased with the increased Si content. The NiTi 90 Si 8 C 2 coating exhibits the highest microhardness (974.08 HV 0.5) and wear resistance (friction coefficients, wear trace, widths loss weight, and wear rate are 0.320, ~1.25 mm, 12.2 mg, and 5.78 × 10−6 g/Nm, respectively). In NiTi 90 Si 8 C 2 coating, Ti 5 Si 3 phase plays a significant role in the second phase strengthening to improve its tribological properties. The above analysis confirms that NiTi 90 Si 8 C 2 coating has optimal tribological properties. [Display omitted] • NiTi 90 Si 8 C 2 coatings are mainly composed of NiTi, NiTi 2 , Ti 5 Si 3 , and TiC phases. • The fragmentation of Ti 5 Si 3 phase is related to the growth of NiTi phase around it. • Ti 2 Si phase and the eutectic structure were found in NiTi 90 Si 8 C 2 coating. • The microhardness of NiTi 90 Si 8 C 2 coating is 1.8 times than NiTi 98 C 2 coating. [ABSTRACT FROM AUTHOR]