Μm Thick Layer Research Articles

Continuously tuneable single electrode pair liquid crystal optical vortex generators

Abstract In this work, we demonstrate the use of two-photon polymerization direct laser writing in the production of continuously tuneable optical vortex beam (OV) generators in a liquid crystal (LC) layer sandwiched between glass substrates. Results are presented that show how an OV generator can be inscribed into a 20 μm-thick LC layer and how the order of the OV beam can be tuned with the application of a voltage. Importantly, only a single pair of electrodes is needed to tune the order of the vortex as the required phase profile is generated through the 3D structuring of the polymer network using the laser writing process. Following the design and fabrication of the LC-OV generator, a Mach–Zehnder interferometer is subsequently employed, in conjunction with polarizing optical microscopy, to characterize the devices to confirm the generation of OVs of different orders and to determine the corresponding chirality. The paper concludes by considering whether these LC-OV generators can function at a range of different operation wavelengths. Such devices would be of potential importance in applications ranging from optical communications to quantum physics.

Influence of compound layer on the corrosion resistance of low alloy steel in a 3.5% NaCl solution

Samples of AISI 4140 low alloy steel were nitrided at different conditions by using plasma nitriding. The optical microscopy observation and x-ray diffraction analysis showed that a 3 ∼ 12 μm thick compound layer composed of ε-Fe2–3N and γ′-Fe4N was formed on the surface after nitriding treatments. The corrosion behavior was evaluated by measuring the anodic polarization curves in a 3.5% NaCl solution along with the observation of corroded surfaces and cross-sectional morphologies using optical and scanning electron microscope. The results indicated that the corrosion resistance of low alloy steel was significantly enhanced through the formation of compound layer. The thickness of compound layer was one important factor in determining its corrosion resistance.

All-dielectric grating-assisted absorption enhancement in a subwavelength mercury cadmium telluride layer for infrared photodetectors

Light absorption enhancement in a 1.5 μm thick mercury–cadmium–telluride (Hg0.762Cd0.238Te, MCT) layer at room temperature utilizing 1D dielectric grating at mid-wave infrared (MWIR) wavelengths (3–5 μm) has been theoretically investigated. The optimized dielectric grating facilitates light diffraction and scattering into the MCT-absorbing waveguiding layer resulting in an increased lateral optical path. The light absorption was improved from ∼37.5% to ∼71% (TE) and ∼70% (TM) at normal incidence. With enhanced absorption, the photocarrier generation rate in the thin layer would be comparable to a bulk 5 μm thick MCT layer. A ∼3× reduction in the MCT layer thickness without compromising absorption has the potential for realizing infrared photodetectors with improved sensitivity at conventional operating temperatures and/or elevated operating temperatures.

Increasing the wear resistance of hip prostheses components using micro-nanostructured thin layers

Evaluation of micro-nanostructured thin layers applicability for increasing the lifetime of rehabilitation systems, mainly hip prostheses, is the aim of the present research. This because, the final objective of the complete project is to improve the quality of human prostheses using micro-nanostructured thin layers. In order to realize these researches, 0.5, 1, and 1.5 µm thick thin layers of TiN and TiO2, were deposited on substrates made of materials currently used for hip prostheses – M30NW steel and CoCr – using physical deposition methods, respectively Cathodic Arc (CA), Direct Current (DC) sputtering and High-Power Impulse Magnetron Sputtering (HiPIMS). After tribological and nanoindentation tests, the 1.5 μm thick TiN and TiO2 thin layers deposited on the steel and CoCr substrates using the DC sputtering method presented superior mechanical properties. Functional characterization of a total hip prosthesis, that have had components coated with these thin layers presented an increased resistance to fatigue wear. After comparative analysis, the main conclusion of the realized researches was that TiN layers with a thickness of 1.5 μm have an increased resistance to fatigue wear in comparison with TiO2 layers, when both are deposited by DC sputtering on M30NW steel and CoCr substrates. It was observed that 1.5 μm thick TiN layers ensures a prolongation by 15% of the lifetime of femoral heads compared to those uncoated.

Characterization of structural and mechanical properties of HfNbTaTiZr refractory high entropy alloy after gas nitriding

This study was initiated to improve surface hardness and wear resistance of a HfNbTaTiZr refractory high entropy alloy (RHEA) by gas nitriding at a medium temperature (600 °C) for 3 h. Structural characterizations conducted by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) equipped scanning electron microscope (SEM) revealed that nitriding led to formation of a 1.5 μm thick surface layer containing precipitates of oxides and nitrides of the alloying elements. Detection of oxides within the surface layer was attributed to the presence residual oxygen in the nitriding atmosphere. Nevertheless, the employed gas nitriding provided remarkably higher scratch resistance compared to the untreated state, as the results of increment in the surface hardness and development of larger compressive residual stress.

Breakdown up to 13.5 kV in NiO/β-Ga2O3 Vertical Heterojunction Rectifiers

Vertical heterojunction NiO/β n-Ga2O/n+ Ga2O3 rectifiers with 100 μm diameter fabricated on ∼17–18 μm thick drift layers with carrier concentration 8.8 × 1015 cm−3 and employing simple dual-layer PECVD SiNx/SiO2 edge termination demonstrate breakdown voltages (VB) up to 13.5 kV, on-voltage (VON) of ∼2.2 V and on-state resistance RON of 11.1–12 mΩ.cm2. Without edge termination, the maximum VB was 7.9 kV. The average critical breakdown field in heterojunctions was ∼7.4–9.4 MV. cm−1, within the reported theoretical value range from 8–15 MV.cm−1 for β-Ga2O3. For large area (1 mm diameter) heterojunction deives, the maximum VB was 7.2 kV with optimized edge termination and 3.9 kV without edge termination. The associated maximum power figure-of-merit, VB 2/RON is 15.2 GW·cm−2 for small area devices and 0.65 GW.cm−2 for large area devices. By sharp contrast, small area Schottky rectifiers concurrently fabricated on the same drift layers had maximum VB of 3.6 kV with edge termination and 2.7 kV without edge termination, but lower VON of 0.71–0.75 V. The average critical breakdown field in these devices was in the range 1.9–2.7 MV. cm−1, showing the importance of both the heterojunction and edge termination. Transmission electron microscopy showed an absence of lattice damage between the PECVD and sputtered films within the device and the underlying epitaxial Ga2O3. The key advances are thicker, lower doped drift layers and optimization of edge termination design and deposition processes.

Deposition of a low-activity type cobalt-modified aluminide coating by slurry aluminizing of a pre-Co-electroplated Ni-based superalloy (IN738LC)

Incorporating the Co element into the β-NiAl phase as a third element enhances the hot corrosion and oxidation properties of aluminide coatings. The deposition of Co-modified aluminide coatings is limited to co-deposition by the pack cementation method or a two-step pack cementation process of Co and Al, so far. This study investigates the possibility of depositing a low-activity type of Co-modified aluminide coating by combining the electroplating process with the slurry aluminizing method. To accomplish this objective, different thicknesses of Co-electroplated layers, deposited by a Watts bath, ranging from 5 to 20 μm are slurry aluminized using a slurry consisting of Al particles as the Al source and a PVA aqueous solution as the binder at 1100 °C for 2 h. Formation mechanisms are discussed through slurry aluminizing of 5, 10, and 20 μm thick Co-electroplated layers at the temperature range of 700–1100 °C with 100 °C intervals at zero time. FE-SEM surface morphology, BSE-SEM cross-sectional observation, surface XRD characterization, and EDS elemental analysis are utilized to characterize the coatings. Results show a critical thickness of the Co layer is required to deposit a defect-free low-activity type of Co-modified aluminide coating, which is determined to be ∼10 μm in this study. The final aluminide coating thickness decreases from ∼140 to ∼65 μm by increasing the Co-electroplated layer thickness from 5 to 20 μm. The identified phases on the surface differ from β-NiAl to β-CoAl by increasing the Co-electroplated layer thickness up to critical value. The Void formation occurs by the Kirkendall effect in coatings with more Co-electroplated layer thickness than the critical value, segregating the coatings within the β-CoAl phase.

Induction of Reparative Dentin Following Pulpotomy with Calcium Hydroxide at Four Week Follow up visit: A Case Report

This in-vivo study used calcium hydroxide pulpotomy of a premolar tooth to investigate the potential for reparative dentin development without causing unfavorable side effects. For cosmetic reasons, a pulpotomy using calcium hydroxide was used to treat a patient's right first premolar tooth. In order to expose the pulp, a round cavity with a diameter of 2 mm was initially created on the occlusal surface using a flat end fissure bur and a high-speed hand piece under adequate cooling conditions. After using sterile cotton pellets to staunch the bleeding, Dycal was applied to the exposed pulp tissue in accordance with the manufacturer's instructions. The tooth was pulled at 4 weeks under local anesthetic, and it was preserved for 24 hours in 4% neutral buffered formaldehyde. After being demineralized, the specimen was imbedded in paraffin. A blind observer used a light microscope fitted with a digital camera and a computer for histometry to examine a series of sections containing pulp tissue that had been longitudinally serially sectioned at a thickness of 6 µm. lastly, the experimental tooth's amount of newly generated hard tissue was measured. The findings indicated that the exposed pulp tissue is only partially covered by the 0.9 ± 0.2 µm thick layer of reparative dentin development. In conclusion, although it does not entirely cover the exposed pulp, calcium hydroxide can promote reparative dentin production and pulpal lesion healing in exposed teeth.

Efficient Micrometer Thick Bifacial Perovskite Solar Cells

AbstractPerovskite solar cells have become promising candidates for thin‐film photovoltaics (PV), but many record cells suffer from losses in current (≈3–4 mA cm−2). This is due to the choice of superstrate configurations (i.e., glass‐side illumination) and thin absorber layers, typically on the order of ≈500 nm. Illumination through a top transparent conductive oxide electrode (substrate configuration) using LiF and Al2Ox as anti‐reflective coatings leads to reflectance losses below 1% is demonstrated. When combined with 1 µm thick absorber layers, substrate configurated bifacial devices have power conversion efficiencies >20%, with minimized reflection losses approaching 98% of their detailed‐balance limits and higher Jsc than their monofacial counterparts. Further analysis is conducted to show there is still a significant fraction of current lost due to poor charge‐carrier extraction (e.g., resistive or low mobility contacts). This is studied by a direct comparison of photoluminescence at short‐circuit versus open‐circuit estimating a 4.5% loss in charge‐carrier collection.

A novel nano-grade organosilicon polymer: Improving airtightness of compressed air energy storage in hard rock formations

Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage (CAES) in hard rock formations. This study introduced a novel approach using a nano-grade organosilicon polymer (NOSP) as a sealant, coupled with an air seepage evaluation model that incorporates Knudsen diffusion. Moreover, the initial coating application methods were outlined, and the advantages of using NOSP compared to other sealing materials, particularly regarding cost and construction techniques, were also examined and discussed. Experimental results indicated a significant reduction in permeability of rock specimens coated with a 7–10 μm thick NOSP layer. Specifically, under a 0.5 MPa pulse pressure, the permeability decreased to less than 1 nD, and under a 4 MPa pulse pressure, it ranged between 4.5×10−6–5.5×10−6 mD, marking a 75%–80% decrease in granite permeability. The sealing efficacy of NOSP surpasses concrete and is comparable to rubber materials. The optimal viscosity for application lies between 95 and 105 KU, and the coating thickness should ideally range from 7 to 10 μm, applied to substrates with less than 3% porosity. This study provides new insights into air transport and sealing mechanisms at the pore level, proposing NOSP as a cost-effective and simplified solution for CAES applications.

9.5–12 GHz solidly mounted bulk acoustic wave resonators utilizing overtone of thickness extension mode

To realize HF bulk acoustic wave (BAW) devices, we have explored the application of integer multiples of overtones (3rd and 6th) of the thickness extension mode in solidly-mounted resonators (SM-BAWRs). When the average thickness of the acoustic films in the Bragg reflector of the SM-BAW device is wavelength (λ)/4, the fundamental mode is strongly excited, but overtone excitation is weak. However, it was found that 0.035λ–0.075λ acoustic layer thickness of a Bragg reflector was suitable for 3rd overtone excitation using a single LiNbO3 (LN) layer and 0.01λ–0.045λ for 6th overtone excitation using a polarization-flipped double LN layer. By using a 1 μm thick LN single thin layer, we successfully excited 3rd overtone at 9.5 GHz. Furthermore, overtones at 9.5 and 12 GHz were excited by bonding 1 μm and 0.9 μm thick LN plates with different polarities.

Assessing the feasibility of laser ablation coating removal (LACR) on legacy bridge steel: Coating removal and adhesion, and effects on mechanical properties

The application of protective organic coatings is one of the most effective and commonly used corrosion mitigation strategies. To maintain the protective nature of coatings on long-term-exposed surfaces such as steel bridge components, coatings must be periodically removed and reapplied. A relatively new method called laser ablation coating removal (LACR), which incorporates a high energy nanosecond pulsed laser beam in combination with a high efficiency filtration system, allows for safe and effective removal of coatings and contamination from metal surfaces. In this study, LACR cleaning is tested on legacy bridge steel components to investigate the effect on substrate cleanliness and steel mechanical properties. These bridge sections were never blasted and contain a 20–100 μm thick mill-scale layer (iron oxide) below several coating layers (including lead-rich coatings). The top micron of the oxide layer is melted by LACR and also thermally insulates the underlying steel and prevents any melting within the metallic substrate. The resulting surfaces are analyzed using microscopy, hardness testing, tensile, and fatigue testing, and it is shown that LACR does not cause any measurable detrimental effects to the bulk mechanical properties of the bridge steel, as well as effectively removes all paint coatings. Furthermore, adhesion testing on LACR-cleaned substrates shows excellent adhesion, qualifying above adhesion requirements for coated steel.

Nonlinear impedance of a micrometer-thick layer of poly(3,4-ethylenedioxythiophen):polystyrene sulfonate

Poly(3,4-ethylenedioxythiophen):polystyrene sulfonate (PEDOT:PSS) is a conductive polymer composite commonly used as a hole-transporting material in various optoelectronic devices. Here, we show that both real and imaginary components of the impedance of a micrometer-thick drop-cast PEDOT:PSS layer measured perpendicular to the layer plane are strongly nonlinear and vary with both amplitude and frequency of the externally applied field. In thinner layers, the impedance approaches linearity; impedances of layers thinner than 100 nm are almost linear within the investigated field and frequency ranges. Impedance nonlinearity is more profound at low-frequencies and almost disappears above 1 kHz. The experimental results are described based on the complex polarization mechanisms prevailing at low-frequencies due to the lazy dynamics of the massive interfacial dipoles formed between PEDOT and PSS chains. The nonlinear impedance of a 2.0 μm-thick layer is utilized for the design and fabrication of a harmonic generator, a frequency adder, and a up/down converter operating at very low frequencies. Operations of a micrometer-thick drop-cast dot of PEDOT:PSS, as a second and third harmonic generator and a passive intermodulator in the frequency range of biological signals are demonstrated. Other polymer composites with large interfacial dipoles are expected to own similar properties.

Influence of the Shrinkage of the Inner Layer of Steel Tubes on Permissible Thermal Load

This paper presents the results of numerical simulations of heat transfer in a tube with a protective chromium layer on the inner surface made of steel, with different shrinkage temperatures. Shrinkage in the steel is an unfavorable phenomenon because it causes cracks in the chrome coating. The cracks contribute to the peeling of the protective material on the inner surface of the tube. Wear and damage to the chrome layer significantly shortens the tube’s service life. The influence of the type of steel with medium carbon content on heat transfer for a sequence of ten, thirty, and sixty heat impulses was examined. Simulations were carried out for two selected steels with clearly different shrinkage temperatures, i.e., 30HN2MFA and X37CrMoV5-1 (1.2343). In 30HN2MFA steel, the shrinkage effect occurred at a temperature of approx. 750 °C, while in X37CrMoV5-1 steel it occurred at a temperature of approx. 870 °C. In the computational model, 30 cross-sections of the three-meter-long tube were analyzed. A time-dependent heat transfer coefficient was calculated in each zone. Heat transfer simulations were carried out using COMSOL version 6.1 software. This paper shows that for X37CrMoV5-1 steel, the shrinkage temperature on the inner surface of the tube was reached after approx. 60 heat impulses, while for 30HN2MFA steel, it was reached after approx. 30. The greatest differences in the number of impulses occurred for a pipe with a 200 µm thick chrome layer.

β -rays induced displacement damage on epitaxial 4H-SiC revealed by exciton recombination

One of the most interesting wide-bandgap semiconductor is 4H-SiC that has an indirect wide-bandgap of 3.3 eV. This material holds great potential to develop power devices that find applications in the field of high-voltage and high-temperature electronics and harsh environments. In this study, we employed complementary noninvasive characterization techniques, including micro-Raman, optical absorption, steady-state, and time-resolved photoluminescence spectroscopy, to investigate the characteristics of a 12 μm thick epitaxial layer of 4H-SiC grown on 4H-SiC. Furthermore, we explored the impact of ionizing radiation on this material, utilizing β-rays and two x-ray sources. The doses are in the range of 1–100 kGy for electrons with energy of 2.5 MeV, 16 kGy for the first x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 28 kV), and 100 kGy for the second x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 100 kV). When exposed to the electron beam, the excitonic band at 3.2 eV exhibits a reduction in its lifetime as the deposited dose increases. In particular, in samples characterized by a greater amount of native defects, both extended and point defects, this effect becomes evident at lower deposited doses. Conversely, in the samples subjected to x-ray irradiation, these effects are not observed. These findings indicate that electron beam irradiation triggers the formation of defects associated with atomic displacement. Ultimately, we have examined the impact of thermal treatments in air, ranging from 100 to 900 °C, to investigate the recovery characteristics of 4H-SiC.

Performance analysis of twin-layer AlTiN and TiCN coated inserts during high speed turning of SS304 with synthetic coolant at 0°C

Industries are facing challenges to machine hard materials in economical ways and to improve the output machining characteristics. In pursuit of effective problem-solving, two distinct sets of AlTiN and TiCN coated inserts were meticulously prepared. Their respective performances were subsequently compared, using the output machining parameters as reference points. AlTiN inserts are fabricated by applying a twin layer consisting of Al50Ti40N (2 µm thickness) and Al60Ti50N (3 µm thickness) over the substrate. The insert obtained from this process has exceptional strength and remarkable toughness. Another substrate is coated with a 3 µm thick layer of TiCN, as TiCN coating offers excellent resistance against shock loads and impact stress. Previous research conducted by scholars has already established the efficacy of using synthetic coolant at 0°C for machining SS304. Hence, synthetic coolant was employed in combination with the aforementioned two types of inserts during their performance testing. A comprehensive analysis revealed that the performance of twin-layer AlTiN inserts surpassed that of TiCN inserts, showcasing superior tool life, reduced tool wear, and enhanced surface finish quality. The replacement of TiCN inserts with AlTiN inserts resulted in an impressive increase of around 70% in tool life and approximately 30% in surface finish quality.

Towards improved antifouling: Exploring xanthan gum hydrogel coatings

This study explored xanthan gum hydrogel coatings as an approach to more environmental friendly fouling control strategies. Xanthan gum served as a filler in a conventional rosin/acrylic coating matrix, leading to the formation of a 150 μm thick gel layer on the coating surface upon seawater exposure. While biocide-free xanthan hydrogel coatings did not have significant antifouling capabilities, a synergistic effect between hydrogel and cuprous oxide was observed. During field tests at the CoaST Maritime Test Center (CMTC), it was found that the cuprous oxide concentration could be reduced by at least 50 wt% for the hydrogel coating without compromising the antifouling performance. Two possible causes were identified. First, the hydrogel coating could maintain a higher release rate over a prolonged period and second, the hydrogel was able to accumulate Cu2+, increasing retention time on the surface, creating a hostile environment. A synergistic enhancement in gel strength, yield point, and flow point was observed when xanthan was combined with konjac mannan. While promising for static applications, the rheological assessments of the different gels highlighted challenges for the application in dynamic settings like moving ships.

Transient Liquid-Phase Sinter-Bonding Characteristics of a 5 um Cu@Sn Particle-Based Preform for High-Speed Die Bonding of Power Devices

To ensure the high-temperature stability of a bondline under next-generation power devices such as SiC semiconductors, a die bonding test was performed by transient liquid-phase (TLP) sinter-bonding using a Sn-coated Cu (Cu@Sn) particle-based preform. Compared to the existing 20 min-bonding result using a 30 μm Cu@Sn particle-based preform, a 5 μm Cu@Sn particle-based preform was used to significantly reduce the bonding time to 5 min, and the optimal levels of the amount of Sn in the Cu@Sn particles, the thicknesses of Sn surface finish layers on the chip and substrate, and compression pressure during the bonding were investigated. The Sn content in the Cu@Sn particles significantly changed the microstructure, including the porosity of the prepared preform. The preform porosity of 0.01% was confirmed after the formation of sufficient Sn shells with an average thickness of about 602 nm at Sn 30 wt%. In addition, in the preform with Sn 30 wt% content, the Sn phase was almost depleted after 3 min after annealing at 250 °C. The Sn finish layer was evaluated in the thickness range of 0.63−4.12 µm, and it was observed that the shear strength of the formed bondline tended to increase with increasing pressure for all Sn layer thicknesses. In particular, when the bonding was carried out at a pressure of 2 MPa using a dummy Cu chip and substrate coated with a 1.53 μm thick Sn layer, the best shear strength value of 36.89 MPa was achieved. In this case, all the Sn phases transformed into intermetallic compound phases of Cu<sub>6</sub>Sn<sub>5</sub> and Cu<sub>3</sub>Sn, and all the phases formed within the bondline, including Cu, exhibited high melting-point characteristics. Therefore, it was determined that there would be no remelting of the bondline or a drastic decrease in mechanical properties in a high-temperature environment below 300 <sup>o</sup>C, as initially intended. By increasing the content of the Sn shell up to 30 wt%, it was possible to achieve a nearly full density (porosity: 0.3%) bondline structure, due to the rearrangement behavior of particles, by maintaining liquid Sn for a long time during the bonding process. In conclusion, the optimal Sn finish thickness was determined to be at the level of 1.5 µm, and the optimal pressure was at the level of 2 MPa. The short bonding time of 5 min represents a significant advance in TLP bonding processes, and it is expected to contribute to a substantial improvement in the die bonding of future SiC power devices.

Rear Surface Passivation for Ink‐Based, Submicron CuIn(S, Se)2 Solar Cells

AbstractA N, N‐dimethylformamide and thiourea‐based route is developed to fabricate submicron (0.55 and 0.75 µm) thick CuIn(S,Se)2 (CISSe) thin films for photovoltaic applications, addressing challenges of material usage, throughput, and manufacturing costs. However, reducing the absorber film thickness below 1 µm in a regular CISSe solar cell decreases the device efficiency due to losses at the highly‐recombinative, and mediocre‐reflective Mo/CISSe rear interface. For the first time, to mitigate the rear recombination losses, a novel rear contacting structure involving a surface passivation layer and point contact openings is developed for solution processed CISSe films and demonstrated in tangible devices. An atomic layer deposited Al2O3 film is employed to passivate the Mo/CISSe rear surface while precipitates formed via chemical bath deposition of CdS are used to generate nanosized point openings. Consequently, Al2O3 passivated CISSe solar cells show an increase in the open‐circuit voltage (VOC) and short‐circuit current density when compared to reference cells with equivalent absorber thicknesses. Notably, a VOC increase of 59 mV contributes to active area efficiencies of 14.2% for rear passivated devices with 0.75 µm thick absorber layers, the highest reported value for submicron‐based solution processed, low bandgap CISSe solar cells.

20CrMnTi surface strengthening based on laser-assisted carburizing grinding

Highly wear-resistant 20CrMnTi surfaces with gradient properties are urgently demanded in manufacturing core components such as shafts and gears. However, balancing productivity, production costs, and energy consumption with existing surface machining and strengthening methods are challenging. Therefore, laser-assisted carburizing grinding is proposed, which combines laser micro-carburizing and grinding tempering to realize the integration of processing and strengthening of the 20CrMnTi surface. The optimal laser power is determined to be 300 W by the dynamic thermal-force coupling effect. A 1300 μm thick metamorphic layer is formed on the surface of 20CrMnTi, and its formation mechanism is analyzed based on the microstructural phase transformation. The surface hardness after laser-assisted carburizing grinding can reach 550 HV. The failure form of the carburized surface is mainly abrasive wear, and the wear loss is reduced to 50% compared to uncarburized surfaces. This study developed an efficient, energy-saving, and controllable integrated method of 20CrMnTi surface machining and strengthening. Meanwhile, the surface strengthening mechanism is explained based on laser micro-carburizing and grinding tempering. The findings provide technical references for manufacturing high-performance 20CrMnTi surfaces and theoretical support for carburized grinding strengthening technology.