Although laser additive manufacturing offers exceptional design flexibility and manufacturing versatility， it is difficult to ensure consistency， repeatability， reliability and predicability in practical applications， which means that conducting research on the theory and control technology of surface integrity and achieving quantitative control over the manufacturing process with the aim of accurately guaranteeing service performance has become pivotal for promoting the precise regulation of the laser additive manufacturing process.Consequently， investigating the process-structure-property-performance (PSPP) relationship through experiments and simulations is an effective strategy to further enhance additive manufacturing capabilities.This paper first provided a brief overview of laser additive manufacturing classifications and described its process control.Subsequently， the influences of surface microstructure， internal defects， surface roughness and residual stress on the mechanical and service performance of laser additively manufactured components were discussed.Furthermore，the impact of introducing machine learning on the nonlinear processes of PSPP was explored.Finally， the future development trends in surface integrity control technologies for laser additive manufacturing were discussed.

Superhydrophobic surfaces exhibit significant application potential in fields such as surface engineering， applied sciences， and micro/nano manufacturing due to their exceptional anti-corrosion， self-cleaning and anti-icing properties.Therefore， the preparation of superhydrophobic surfaces and the optimization of related processes have become a research hotspot in current academic research.Among various approaches， laser processing and electrodeposition have garnered extensive attention in superhydrophobic surface fabrication due to their mature process technology.Herein， this paper systematically reviewed the current research status of laser processing，electrodeposition and their hybrid techniques for fabricating superhydrophobic surfaces.First，the definition of superhydrophobic surfaces and wettability theory were elaborated.A detailed analysis of the mechanisms governing electrodeposition and laser etching was presented， and relevant research outcomes were summarized.Second， regarding the laser-electrodeposition hybrid process， its advantages and research progress in fabricating superhydrophobic surfaces were summarized.Finally， current technical challenges in applying hybrid techniques were discussed， and future research directions were proposed.

Reducing friction loss is an important aspect of improving engine efficiency.The cam tappet mechanism， as an important component of the engine gas distribution mechanism， accounts for over 70%of frictional energy consumption in the engine gas distribution mechanism by friction.Therefore，investigating the tribological performance of cam tappet friction pairs is indispensable for ensuring optimal engine operational efficiency.Among various surface treatment technologies， laser surface treatment has been widely applied to improve the tribological properties of materials，demonstrating excellent performance in friction reduction and wear resistance.This paper reviewed recent advances in wear mechanisms of cam tappet friction pairs and summarized key factors influencing their tribological performance.The friction-reduction effect of the cam tappet friction pair was analyzed from three aspects: laser quenching， laser-cladded coating and laser surface texture， which could provide a reference for subsequent researchers in this direction.Finally， combining the existing research and future demands， the prospects for applying laser surface treatment technologies to friction-reduction studies of cam tappet systems were provided.

To enhance the hardness and wear resistance of laser-cladded TiC-reinforced Inconel718 composite coatings， solution and aging treatments were applied to the TiC/Inconel718 composite coatings.The effects of heat treatment and different TiC contents on the microstructure， hardness and friction and wear properties of the TiC/Inconel718 composite coatings were investigated.Results showed that the microstructure of the TiC/Inconel718 composite coating underwent significant changed after heat treatment.Most of the Laves phase dissolved， and at the same time， (Nb， Ti)C carbides precipitated， making the precipitation phase more uniform.In addition， heat treatment also promoted the precipitation of the strengthening phase and the formation of fine-sized TiC.The formation of carbides，the precipitation of strengthening phases after heat treatment and the precipitation of fine-sized TiC significantly enhanced the hardness and friction and wear performance of the composite coating.After heat treatment， the composite coating with a TiC content of 30%(mass fraction) had the highest hardness， reaching 764 HV0.2.Under high-temperature conditions， the wear resistance of heat-treated composite coatings was enhanced.With increasing TiC content， the wear mechanism transitioned from adhesive wear and abrasive wear to mild abrasive wear.Besides， the improvement in coating hardness and high-temperature wear resistance was attributed to the precipitation of strengthening phases after heat treatment and the reinforcing effect of TiC particles at different scales.

To further investigate the microstructural properties of DZ125 nickel-based superalloy after laser cladding repair，this study employed laser cladding technology to deposit CoCrW powder onto the substrate surface，thereby fabricating a cladding layer.Subsequently，both the base material (BM specimen) and the cladded specimen (LC specimen) underwent a 100 h high-temperature exposure test at 700 °C.Salt films were applied to the surfaces of both the base material and cladded specimens， followed by a 100 h exposure test under identical high-temperature conditions.Meanwhile， the effects of high-temperature oxidative corrosion on the alloy’s microstructure， microhardness and compositional characteristics were analyzed， and the corrosion resistance of the cladding layer under salt-deposited hot corrosion conditions was explored.Results showed that the microhardness increased gradually from the base material to the transition layer and the cladding structure， and the hardness of the cladding structure was up to 559 HV0.2.After high-temperature exposure， the specimens exhibited significant oxidation， with those in the hot salt environment demonstrating exacerbated oxidation severity.Compared to salt-free conditions， the oxide layer thickness showed a significant increase under salt deposition，accompanied by more extensive spalling pits.However，compared to the BM specimen，the LC specimen demonstrated milder oxidation in both environments， indicating that the laser-cladded microstructure possessed superior corrosion and oxidation resistance relative to the base material.

To optimize the process parameters for fabricating biomedical Ti-15Mo alloy via selective laser melting (SLM)， this work systematically investigated the effects of laser processing parameters on the relative density， microstructure， mechanical properties， and corrosion resistance of specimens by optical microscopy (OM)， X-ray diffraction (XRD)， scanning electron microscopy (SEM)， universal testing machines and electrochemical workstations.Results showed that with increasing laser energy density， the relative density of Ti-15Mo alloy first progressively increased and then stabilized.The specimens exhibited equiaxed grains along the vertical direction and columnar grains parallel to the deposition direction， with a single β-phase of bcc structure constituting the phase composition.In addition， the mechanical properties of the specimens showed a positive correlation with their relative density.When the laser power was 175 W，the scanning speed was 1 500 mm/s，and the scanning spacing was 80 μm， the relative density of the as-prepared specimen reached 99.84%， and the comprehensive performance was the best.The specimens exhibited the ultimate tensile strength of 801.0 MPa， the elongation of 24.0%and the elastic modulus of 90.6 GPa.Moreover， the specimen demonstrated excellent corrosion resistance with a current density of 0.059 μA/cm2 and corrosion rate of 0.05 μm/a，meeting the stringent requirements for biomedical implant materials.

Marine oil and gas engineering equipment suffers significant damage due to seawater corrosion and mechanical wear.Medium-entropy alloys， with their combined wear and corrosion resistance， are considered ideal materials for surface protective coatings.In this study， a FeCrBSi medium-entropy alloy coating was prepared on the surface of 316L stainless steel via laser cladding technology.The microstructure and tribocorrosion coupling behavior of the cladded layer were analyzed using X-ray diffraction (XRD)， metallographic microscopy and electrochemical corrosion and tribological tester.Results showed that the cladding layer consisted of dual-phase FCC and BCC solid solutions.The cladded zone was primarily composed of dendritic structures， while the bonding zone exhibited planar crystals.The average hardness of the FeCrBSi medium-entropy alloy coating reached 939 HV0.2， approximately 4.4 times that of the 316L stainless steel substrate.As the applied frictional load increased， the coefficient of friction of the coating decreased， with average values ranging from 0.2 to 0.5.The maximum wear volume was 0.052 mm3， indicating a significant improvement in wear resistance compared to the substrate.Electrochemical testing in a 3.5%(mass fraction) NaCl solution demonstrated superior corrosion resistance compared to 316L stainless steel， as indicated by a self-corrosion potential of -0.05 V and a corrosion current density of 1.45×10－7 A/cm2.Under the combined effect of frictional load and externally applied corrosion potential， both the average current density and wear volume increased with increasing potential， while the friction coefficient decreased.A synergistic interaction between corrosion and wear was observed.Notably， corrosion-induced wear contributed over 92.5%to the total material loss， demonstrating its dominant role.

To improve the wear-resistant performance of cold work die steel and prolong its service life， hard TiC particles were introduced as reinforcing phases.Laser cladding technology was employed to fabricate both Ni60 and TiC-reinforced Ni60 composite cladding layers on Cr12MoV cold work die steel.Subsequently， the microstructure and friction and wear properties of the cladding layer were comparatively studied by scanning electron microscope，ball-disc high-temperature friction and wear testing machine and ultra-depth-of-field microscope.Results showed TiC ceramics melted into the molten pool of the cladding layer during the laser cladding process， and two different scales of TiC strengthening phases precipitated during the cooling process.The fine TiC phases were dispersed in the cladding layer， effectively inhibiting the grain coarsening within the microstructure， while the coarse blocky TiC aggregated together to form hard phase particles.The two different scales of TiC significantly enhanced the hardness and wear resistance of the cladding layer.The average microhardness of the TiC strengthened Ni60 composite cladding layer reached 869.5 HV0.2， which was 2.03 times that of Cr12MoV cold work die steel.The strengthening effect of TiC at different scales effectively prevented the micro-cutting action of abrasive particles，thereby enhancing the tribological performance of composite cladding layer.Furthermore， the addition of TiC reduced the friction coefficient of the composite cladding layer， and the wear volume decreased by approximately 86.4%compared with Cr12MoV cold work die steel.The wear mechanisms of the composite cladding layer were mainly abrasive wear and slight adhesive wear.

30CrMnSiA steel is extensively utilized in specialized tooling components， which frequently experience fatigue fractures and other damage mechanisms under cyclic stress during service.In this work，the laser cladding technology was adopted，and the microstructure and mechanical properties were analyzed based on process experiments.The optimal parameters were selected to perform laser repair on the damaged fork-shaped part of 30CrMnSiA， and its fatigue life was tested by a fatigue testing machine.Results showed that the microstructure within the repair layer was dense.The bonding interface between the repair layer and the base material was a typical metallurgical bonding，and no defects such as cracks occurred.The strength of the weld seam was higher than that of the base metal， and the tensile fracture was basically at the base metal.Besides，the specimen achieved a fatigue cycle count of 606 501，representing a 21.3%improvement in fatigue life compared to standard parts， meeting all operational requirements for specialized tooling components.

To improve the microstructure of the alloy coating and enhance the mechanical properties of the cutter head in coal mining machines，Fe-based alloy cladding layers (S1 and S2) were fabricated on mining cutter head surfaces at two scanning speeds of 0.5 m/min and 12 m/min.The metallographic microstructure， mechanical properties and tribological performance of coatings were systematically characterized by scanning electron microscopy (SEM)， Vickers hardness tester， and X-ray diffraction (XRD).Results showed both coatings exhibited dense microstructures without defects such as pores or cracks.The top layer of both laser-clad coatings consisted of equiaxed crystals， the middle layer was composed of columnar crystals， and the bottom layer consisted of planar crystals.Moreover， the overall microstructure of the S2 coating was finer than that of S1， and the overlay layers were primarily composed of an α-Fe solid solution， Cr2B and FeNi.The γ-Fe phase precipitated in S1， while the diffraction angle of the α-Fe phase in S2 shifted to a lower angle than that of S1.Both coatings had higher microhardness than the substrate，with the S2 coating showing the highest microhardness of 651 HV0.5.The strengthening mechanisms of the coating mainly included grain refinement strengthening and solid solution strengthening.Besides， S2 demonstrated the best tribological performance， and the wear rate of the substrate was 7.3 times that of S2.The wear mechanism of the substrate was adhesive wear， whereas that of the coatings was primarily abrasive wear.

In order to investigate the effects of processing parameters on the microstructure and mechanical properties of the AlCoCrFeNi2.1 eutectic high entropy alloy(EHEA)， an orthogonal experimental design coupled with a comprehensive-scoring method was used to preliminarily identified the optimal laser cladding conditions.Among the tested combinations， Sample 4 (laser power 1 800 W， scanning speed 360 mm/min， powder-feed rate 2.1 r/min) and Sample 5 (laser power 1 800 W， scanning speed 420 mm/min， powder-feed rate 2.4 r/min)received the highest scores.These two specimens were then subjected to multi-pass， single-layer laser cladding， and their microstructures and mechanical properties were systematically characterized.Results showed that the laser-cladded AlCoCrFeNi2.1 EHEA coating was composed predominantly of dual FCC and BCC phases.In the multi-pass coating， Sample 5 displayed a surface dominated by uniform equiaxed grains，whereas Sample 4 exhibited a mixture of columnar and equiaxed grains with larger， irregular sizes.Further investigations showed that Sample 5 possessed superior microhardness and wear resistance:an average hardness of 323.7 HV1.0，an average friction coefficient of 0.64，and markedly lower wear rate (1.16×10－6 mm3∙N－1∙mm－1) and wear volume (14.4 mm3) than Sample 4.Accordingly， the optimal laser-cladding parameters for AlCoCrFeNi2.1 EHEA were determined to be a laser power of 1 800 W， a scanning speed of 420 mm/min， and a powder-feed rate of 2.4 r/min.

To study the effect of different rare earth Y2O3 contents on the microstructure of laser-cladded Ni-based WC ceramic composite coatings， the Ni-based WC ceramic composite coatings were melted on the surface of 9SiCr using 900W YAG solid laser.The effects of Y2O3 on the structure of the composite coatings were systematically investigated by means of scanning electron microscope (SEM) and X-ray diffraction(XRD).Results showed that the addition of Y2O3 could cause alterations in the relative phase composition ratios within the coating，and Y elements were mainly concentrated at the grain boundary edges.Adding a suitable amount of Y2O3 effectively reduced the coating defects during the cladding process， improved coating densification， promoted more homogeneous microstructural distribution， and significantly refined grain size.When the amount of Y2O3 was 1.5%， the microstructure uniformity of the as-prepared coating was the highest.