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Continuous exterior insulation is such an obvious thing to do-and we are finally getting serious about it-but we still seem to go out of our way to defeat its intent.

Titanium (Ti) and its alloys have been widely employed in aeronautical, petrochemical, and medical fields owing to their fascinating advantages in terms of their mechanical properties, corrosion resistance, biocompatibility, and so on. However, Ti and its alloys face many challenges, if they work in severe or more complex environments. The surface is always the origin of failure for Ti and its alloys in workpieces, which influences performance degradation and service life. To improve the properties and function, surface modification becomes the common process for Ti and its alloys. The present article reviews the technology and development of laser cladding on Ti and its alloys, according to the cladding technology, cladding materials, and coating function. Generally, the laser cladding parameters and auxiliary technology could influence the temperature distribution and elements diffusion in the molten pool, which basically determines the microstructure and properties. The matrix and reinforced phases play an important role in laser cladding coating, which can increase the hardness, strength, wear resistance, oxidation resistance, corrosion resistance, biocompatibility, and so on. However, the excessive addition of reinforced phases or particles can deteriorate the ductility, and thus the balance between functional properties and basic properties should be considered during the design of the chemical composition of laser cladding coatings. In addition, the interface including the phase interface, layer interface, and substrate interface plays an important role in microstructure stability, thermal stability, chemical stability, and mechanical reliability. Therefore, the substrate state, the chemical composition of the laser cladding coating and substrate, the processing parameters, and the interface comprise the critical factors which influence the microstructure and properties of the laser cladding coating prepared. How to systematically optimize the influencing factors and obtain well-balanced performance are long-term research issues.

To investigate the role of different distribution forms of Fe–Cr–C cladding layer in the impact abrasive wear performance of Hadfield steel, the over-lapped Fe–Cr–C cladding layer and dot-shaped Fe–Cr–C cladding layer were deposited, respectively, by plasma transferred arc (PTA) cladding on Hadfield steel. The microstructure, microhardness and impact abrasive wear performance of the two cladding layers under the impact of glass sand, granite and quartz sand were investigated. The results showed that both microstructures of the cladding layers were hypoeutectic Fe–Cr–C microstructures. The average microhardness of the over-lapped cladding layer and dot-shaped cladding layer was around 560 HV0.2 and 750 HV0.2, respectively. The over-lapped Fe–Cr–C cladding layer could only improve the impact abrasive wear resistance of the Hadfield steel under the wear condition of the glass sand. Meanwhile, the dot-shaped Fe–Cr–C cladding layer could improve the impact abrasive wear resistance of the Hadfield steel under all the three kinds of the abrasives because of the overall strengthening effect of its convex shape and the hypoeutectic FeCrC microstructure.

Because of inadequate hardness, low resistance to wear, and excess friction coefficient of titanium, and its alloys are limited in their applicability. Cladding, a type of surface modification process, is used to create layers on titanium and its alloys that have superior mechanical qualities, wear characteristics, oxidation resistance at high temperatures, and good biocompatibility. Material selection is critical for achieving the increased qualities mentioned above, in addition to various cladding techniques and associated process parameters. A review of the outcomes of various common wear-resistant cladding techniques applied to the titanium alloy surface is the subject of this study. The most important functional claddings in this domain are also presented and investigated in depth. The present issues and future initiatives are also discussed, with an emphasis on identifying knowledge and technological gaps as well as attempting to establish future research possibilities. On this foundation, it is suggested that in the coming years, resistant-to-wear cladding with significant improvements in toughness and hardness should progress on the path of smart manufacturing techniques, optimising and precisely customising microstructural configurations, and developing numerical simulation techniques of cladding.

Nowadays, public buildings are clad on the outside, many with stone-clad facades. Energy requirements have changed a lot in the last 20–25 years, and the latest required value of the thermal conductivity of masonry is 0.24 W/m2K. The relevant requirements, available materials, and fastening technology options have changed significantly. Our research covers a comprehensive analysis of these systems, the selection of stone cladding materials, and the suitability and use of individual stone types for facade cladding, as well as an energy examination of layered wall systems and the development of fastening elements, including the material structure of the elements and possible design and fastening methods. In the original university research, we also developed an applied technology for several product manufacturing companies in order to obtain approval for industrial application. In this article, we summarize the results of our research, the building structure and building physics issues, the necessary fastening technology design, and the main aspects of selecting stone tiles regardless of the manufacturing companies. The goal of our university research was the introduction and structural development of assembled stone facade cladding in Hungary, a development that continues to this day. The assembled stone cladding system we developed has been used to cover the facades of thousands of buildings in Hungary.

Here, we numerically propose and demonstrate a technique to couple light between two multi-core fibers (MCFs) using long-period gratings (LPGs). The light is coupled from one core of the input MCF to all cores of the output MCF. For that, an LPG is inscribed in the input core of the input MCF and identical LPGs are inscribed in all cores of the output MCF. First, the light is launched into the input core of the MCF and the optical power is transferred to the cladding due to the LPG inscribed in that core. The optical power in the cladding is then transferred to the other MCF cladding by evanescent field coupling. The optical power in the cladding of the output MCF is distributed by all its cores due to the identical LPGs inscribed in them. We optimized the LPGs period, their lengths and offset distance to increase the power transfer at 1480 nm. We achieved a power transfer of 92% of the input power, distributed by all MCF cores, in 10.6 cm of length. We also studied the power transfer sensitivity to the LPGs period.

This study aims at improving the coating properties and cladding efficiency in composite material laser cladding. Using Taguchi orthogonal experimental design, the correlation between processing parameters and index of cladding quality had been investigated. By altering the input of laser power, scanning speed, gas flow, and tungsten carbide powder ratio in laser cladding setup, their influence on the micro-hardness and wear resistance of the clad as well as the cladding efficiency had been studied. This study achieved processing parameter optimization with grey relational analysis by combining multiple objectives. Results showed that the micro-hardness and wear resistance of the clad were significantly affected by the WC powder ratio in the composite. Also, the laser power denoted a significant impact on the cladding efficiency. To obtain the clad with maximum micro-hardness and minimum wear volume while also attaining the maximum cladding efficiency, grey relational analysis was utilized to combine these multiple objectives in optimization. The processing parameter set obtained from optimization met the targets and showed a small-scale error rate of 4.92% in the grey relational grade prediction. This study verified the applicability and provided the theoretical basis for multiple-objective optimization of the coating properties and cladding efficiency in composite laser cladding.

W NbMoTa refractory high-entropy alloys with four different tungsten concentrations ( = 0, 0.16, 0.33, 0.53) were fabricated by laser cladding deposition. The crystal structures of W NbMoTa alloys are all a single-phase solid solution of the body-centered cubic (BCC) structure. The size of the grains and dendrites are 20 μm and 4 μm on average, due to the rapid solidification characteristics of the laser cladding deposition. These are much smaller sizes than refractory high-entropy alloys fabricated by vacuum arc melting. In terms of integrated mechanical properties, the increase of the tungsten concentration of W NbMoTa has led to four results of the Vickers microhardness, i.e., = 459.2 ± 9.7, 476.0 ± 12.9, 485.3 ± 8.7, and 497.6 ± 5.6. As a result, NbMoTa alloy shows a yield strength (σ ) and compressive strain (ε ) of 530 Mpa and 8.5% at 1000 °C, leading to better results than traditional refractory alloys such as T-111, C103, and Nb-1Zr, which are commonly used in the aerospace industry.

As one of the lightest structural metals, the application breadth of aluminum alloys is, to some extent, constrained by their relatively low wear resistance and hardness. However, laser cladding technology, with its low dilution rate, compact structure, excellent coating-to-substrate bonding, and environmental advantages, can significantly enhance the surface hardness and wear resistance of aluminum alloys, thus proving to be an effective surface modification strategy. This review focuses on the topic of surface laser cladding materials for aluminum alloys, detailing the application background, process, microstructure, hardness, wear resistance, and corrosion resistance of six types of coatings, namely Al-based, Ni-based, Fe-based, ceramic-based, amorphous glass, and high-entropy alloys. Each coating type’s characteristics are summarized, providing theoretical references for designing and selecting laser cladding coatings for aluminum alloy surfaces. Furthermore, a prediction and outlook for the future development of laser cladding on the surface of aluminum alloys is also presented.

We prepared three kinds of Ni based alloy cladding coatings on 316L stainless steel at different power levels. The microstructure of the cladding layer was observed and analyzed by XRD, metallographic microscope, and SEM. The hardness of the cladding layer was measured, and the wear resistance of it was tested by a friction instrument. The results show that the effect of laser cladding is good, and it has good metallurgical bonding with the substrate. Different microstructures such as dendritic and equiaxed grains can be observed in the cladding layer. With the increase in laser power, more equiaxed and columnar dendrites can be observed. The phase composition of the cladding layer is mainly composed of γ–Ni solid solution and some intermetallic compounds such as Ni3B, Cr5B3, and Ni17Si3. The results of EDS show that there are some differences in the distribution of C and Si between dendrites. The hardness of the cladding layer is about 600 HV0.2, which is about three times of the substrate (~200 HV0.2). Through the analysis of the wear morphology, the substrate wear is serious, there are serious shedding, mainly adhesive wear, and abrasive wear. However, the wear of the cladding layer is slight, which is abrasive wear, and there are some grooves on the surface.