Material Processing Technology Research Articles

Research on Steel Surface Defect Detection Based on YOLOv5 with Attention Mechanism

Due to the irresistible factors of material properties and processing technology in the steel production, there may be different types of defects on the steel surface, such as rolling scale, patches and so on, which seriously affect the quality of steel, and thus have a negative impact on the economic efficiency of the enterprises. Different from the general target detection tasks, the defect detection tasks have small targets and extreme aspect ratio targets. The contradiction of high positioning accuracy for targets and their inconspicuous features makes the defect detection tasks difficult. Therefore, the original YOLOv5 algorithm was improved in this paper to enhance the accuracy and efficiency of detecting defects on steel surfaces. Firstly, an attention mechanism module was added in the process of transmitting the shallow feature map from the backbone structure to the neck structure, aiming at improving the algorithm attention to small targets information in the feature map and suppressing the influence of irrelevant information on the algorithm, so as to improve the detection accuracy of the algorithm for small targets. Secondly, in order to improve the algorithm effectiveness in detecting extreme aspect ratio targets, K-means algorithm was used to cluster and analyze the marked steel surface defect dataset, so that the anchor boxes can be adapted to all types of sizes, especially for extreme aspect ratio defects. The experimental results showed that the improved algorithms were better than the original YOLOv5 algorithm in terms of the average precision and the mean average precision. The mean average precision, demonstrating the largest increase among the improved YOLOv5 algorithms, was increased by 4.57% in the YOLOv5+CBAM algorithm. In particular, the YOLOv5+CBAM algorithm had a significant increase in the average precision for small targets and extreme aspect ratio targets. Therefore, the YOLOv5+CBAM algorithm could make the accurate localization and classification of steel surface defects, which can provide a reference for the automatic detection of steel defects.

Modeling and analysis of the plasma primary atomization for controllable preparation of high-quality spherical metal powders

Plasma primary atomization (PPA) is a unique and critical process in the plasma atomization (PA), which is a highly recognized materials processing technology for producing high-quality spherical powder, but there lacks of in-depth understanding and models on how the metal wire is converted into high-quality spherical metal powders. Therefore, experimental observations and theoretical analysis on the PPA process were carried out to reveal the behavior of molten metal for controllable preparation of the metal powders. Firstly, the typical stages in the PPA were firstly revealed by experimental observations. Secondly, heat and mass transfer models on PPA were established to reveal how the molten metal is generated and transferred on the wire surface. Thirdly, the behavior of the molten metal in PPA was phenomenologically modeled and quantitatively analyzed based on the experimental observations and the proposed models. As such behavior determines the average size and yield of the produced powders, two key influencing parameters were identified to quantitatively reflect the melting and transfer behavior of the molten metal respectively. Then, calculation equations for them were established based on the proposed models of PPA and then verified. With the proposed models of PPA and the established calculation equations of the key influencing parameters, the quality of the produced powders may be quantitatively controlled by optimal design of the plasma torch and selection of the processing parameters of PA.

Microstructure and mechanical properties of NiTi nanoporous structures fabricated with dealloying process

Dealloying is an emerging material processing technology to fabricate nanoporous functional surface. Systematic characterization of microstructure and mechanical properties for dealloyed surface is a basis for tailoring dealloying parameters. This paper aims to investigate the effect of dealloying treatment on the evolution of microstructures and mechanical properties of NiTi alloy. Firstly, nanoporous layer is fabricated with electrochemical dealloying method to dissolve nickel element selectively from NiTi alloy. Secondly, the microstructures of dealloyed layer are characterized and analyzed with microscopic test methods. The release characteristics of nickel ions from the sample surface before and after dealloying treatment were evaluated using SBF immersion tests. Thirdly, the mechanical properties of NiTi nanoporous structure are evaluated with nanoindentation and micro scratch tests. The results show that both elastic modulus and nanohardness of the NiTi nanoporous layer are over 80% lower than those of the matrix material. The super-elastic property of NiTi alloy is weakened. Meanwhile, the scratching force at the same scratching depth is reduced by over 30% after dealloying process. Instead of severe plastic deformation, irregular brittle fracture occurs along the scratched groove and it demonstrates the plasticity degradation of dealloyed surface. Finally, the weakening mechanism of nanoporous structures fabricated with dealloying treatment is discussed.

Comprehensive study of health effects of plasma technology occupational environment: Exposure to high frequency and intensity noise and toxic gases

ObjectivesTo evaluate on animal models the health effects of the combined or separate exposure to main chemical and physical hazards of plasma-based material processing technology environment. Materials and methodsMale Wistar rats were exposed to actual levels of hazardous factors in plasma technology occupational environment: i.e., ozone and nitrogen oxides (O3 and NOx) in respective concentrations of 0.5 mg/m3 and 1.0 mg/m3 and high-frequency (1000–1600 Hz) of 112 dB intensity noise for 3 h/day, 5 days/week for 12 weeks, with a recovery period of 1 month. ResultsExposure to noise or its combination with chemical factors (ozone, nitrogen oxides) causes non-specific CNS changes testifying for significant excitation dominance, especially in the case of joint exposure. Histological examination of rats’ brain in experimental revealed a pronounced increase in blood filling of small vessels on the tenth day of the experiment, with subsequent intensification of vascular alterations and eventually to cerebral edema. The exposure to noise significantly reduced total thymus, bone marrow and spleen cell numbers and these was also more pronounced under the joint impact of noise and toxic gases. Thymus, but not bone marrow or spleen, mitotic activity was as well reduced under the same modes of exposure. Cytological investigation of film preparations of subcutaneous connective tissue revealed that joint exposure led to microcirculatory disorders, increased number of dark mast cells and reduced degranulation processes indicative of increased autoregulatory processes effective at microvasculature level. ConclusionsHigh-frequency and intensity noise is main stressor factor that has negative impact on CNS and immune system, morphology and functioning of hematopoietic organs (spleen, bone marrow, thymus) and connective tissue. Its negative impact is significantly potentiated by concurrent exposure to ozone and nitrogen oxide, while exposure only to these toxic gases has no significant effect on the above targets.

Experimental Study of Nano-Structural Coatings Formed by Microwave Plasma

A novel microwave plasma (MP) torch on a rectangular waveguide with two magnetron sources 2.45 GHz and an experimental setup are designed to perform hydroxyapatite (HA) coatings on metallic and dielectric substrates. Operating regimes of a such torch are investigated. Experimental studies have proved the advantages of this method of HA coating in comparison with analogous techniques. The proposed design is suitable for application in other technologies of different materials processing. Results obtained in the present study help to better understand the processes of nano-structural layer formation on solid substrates.

Identifying the physical mechanisms of polycrystalline lead salt photoconductors

Polycrystalline infrared lead salt detectors exhibit exceptionally high sensitivity near room temperature and, as such, are ubiquitous in commercial instruments such as spectrometers and flame detectors. The underlying physical mechanism behind this remarkable performance has been the subject of speculation for many years. In this treatise, data from work performed at BAE Systems and St. John's Optical Systems and from the published literature are analyzed to identify common mechanisms that contribute to the photoconductivity of polycrystalline lead salt detectors from a multitude of material deposition and process technologies, and it was concluded that much of the behavior can be attributed to surface-related phenomenon. Physical models are proposed to explain the observations. Finally, there is a brief description of measurements related to noise in these complex structures, indicating the importance of ohmic contacts, but the observed low frequency spectral noise density remains a mystery.

Optimization of multistage femtosecond laser drilling process using machine learning coupled with molecular dynamics

Although femtosecond laser percussion drilling is widely used in many key industrial manufacturing fields, the quality of micro-holes limits its service performance. The traditional trial and error method and physical model are always time and cost consuming for process optimization. To address this problem, a process optimization framework coupled with molecular dynamics simulation, machine learning and a high-throughput optimization algorithm is proposed. The physical information obtained by molecular dynamics enriches the data set used to train machine learning model, and thus reducing the amount of data required. Machine learning can quickly and accurately establish the regression model between laser parameters and target machining performance, and high-throughput optimization algorithm is responsible for determining the optimal process in the process space. For femtosecond laser percussion drilling, a new four-stage drilling process is proposed and optimized using the coupling process optimization framework to solve efficiency and quality problems. Finally, the experimental validation for Ni-based single crystal superalloy verifies the reliability of the optimized process. The framework can be extended to other complex systems to realize process optimization with high efficiency and low cost in laser material processing technology.

Sustainability of microwave heating in materials processing technologies

In this cutting-edge technology, industrial and competitive era, the sustainability of any manufacturing processes needs utmost attention. Sustainability itself is a broad term which can be related to the number of parameters of any process may be its efficiency, product quality, power and time consumptions, suitability of a variety of materials etc. Such parameters of sustainability can only be achieved by finding novel routes of manufacturing or materials processing technologies. The conventional systems are going out of trends due to higher energy demands and higher time consumption to achieve the desired goals instead of using conventional processes. A lot of research is going in this direction for developing processes which are clean and green methods. Microwave Processing (MWP) of materials and heating technology is one such novel route which can be used for processing of ceramics, metal matrix composites (MMC), fibre reinforced plastics (FRP), alloys, metals, material joining, coating, cladding, materials synthesis etc. The present work reports the various applications of microwave energy in various materials processing technologies, its advantages and sustainability issues. The microwave heating started with the food industry and now has penetrated its presence in the domain of metals. The microwaves are now used for processing of a variety of materials, including bulk metals in the area of cladding, joining, melting and casting. The broad perspectives of using MWP are highlighted and recent innovative contributions in this area are highlighted. Focus is on the recent trends and techniques used in microwave materials processing and its effective utilization can be compared to conventional processes. Some parameters for comparison to sustainability of various manufacturing/processing technologies are discussed in the present work.

Material composition and processing technology for quartz-kaolin rocks of the Khodzhakul deposit

This paper describes the material composition and processing technology for quartz sand isolated from the quartz-kaolin rock of the Khodzhakul deposit group located in the Republic of Uzbekistan. The chemical, mineral, and grain-size compositions have been studied for the quartz-kaolin rocks and a processing technology has been developed for the resulting sand. Material composition of the sand was established by X-ray phase analysis after calcination at 900–1350 °C, as well as using chemical and IR spectroscopic analysis methods. The effect of dilution of the kaolin suspension isolated by decantation has been studied. According to the research results, the best processing values are observed when using Uniflok flocculant and sodium phosphate solution as the dispersant at a ratio of 1.0 : 1.0. An 8-EVSV-16/100 electromagnetic separator was used to study the additional processing of quartz sand in an electromagnetic field. Electromagnetic treatment of the quartz product allows removing up to 78.6 % of iron impurities. Based on the results obtained, a process flow was proposed for the extraction and separation of quartz sand from the original rocks and its additional processing. This process includes hydraulic extraction of the raw materials, primary classification in hydrocyclones, quartz flocculation and washing of kaolin slimes, drying of the quartz product, and dry electromagnetic separation using a roller separator. The process includes process water circulation. The quartz sand obtained using this technology contains 97.8 wt% of SiO2, less than 0.05 wt% of Fe2O3, and 1.20 wt% of Al2O3. The quartz product with the specified composition may be used for the manufacture of colorless transparent glass.

Effects of oxygen content on microstructure and mechanical properties of 18Ni300 maraging steel manufactured by laser directed energy deposition

Compared to conventional material processing technologies, laser directed energy deposition (LDED) belonging to additive manufacturing (AM) has many advantages and enormous commercial potential. However, the effect of external factors on the deposition process has not been completely revealed such as the oxygen content in the manufacturing environment. 18Ni300 as maraging steel has excellent mechanical performance, but oxidation inside parts could induce metallurgical defects like inclusion or cracks and impair the service life of parts. Therefore, this paper focuses on the microstructure and mechanical properties of 18Ni300 maraging steel fabricated by LDED under different oxygen contents. The control of oxygen content in the environment was achieved by changing the argon content. Experimental results indicated that the forming accuracy of specimens and process stability were effectively improved at both 500 ppm and 50 ppm oxygen contents. The width of equiaxed grain region, grain growth orientation and primary dendritic arm spacing were significantly affected by gaseous environment. In the low oxygen content group, higher microhardness values were obtained due to the effect that similar to heat treatment. The ultimate tensile strength of samples reached to 908 MPa under 50 ppm oxygen content, which exceeded the tensile strength of wrought components.

The microstructure evolution and precipitation behavior of TiB2/Inconel 718 composites manufactured by selective laser melting

Additive Manufacturing is an advanced material processing technology emerging in recent years. However, coarse columnar grain structure of additive manufactured metals reduces the performance of the material. Facilitating the columnar to equiaxed transition (CET) has become a research hotspot. In this paper, the equiaxed grain of additive manufactured Inconel 718 was achieved by adding TiB2 particles. Simultaneously, the microstructure evolution and precipitation behavior with nano-TiB2 particles addition were studied. The results show that the grain morphology of Inconel 718 exhibited coarse columnar grains with epitaxial growth and strong <100> texture. When 3 wt% TiB2 was added, the columnar grains became finer, further increased the content of TiB2 to 5 wt%, the equiaxed grains were obtained and the texture intensity decreased significantly. In addition, TiB2 partially melted under the high laser energy changed the phase precipitation behavior of Inconel 718 from chain-like Laves phase to reticulated (γ + M3B2) eutectics, which lead to the hardness increased from 276 HV to 578 HV when 5 wt% TiB2 was added. After heat treatment, the precipitation of high density γ′ and γ″ strengthening phase were promoted the hardness increased by 87% to 516 HV in Inconel 718. However, the hardness of TiB2 reinforced samples showed a little change, which could be attributed to the partial dissolution of M3B2 boride during the heat treatment.

Optimal Design of Multilayered Radar Absorbing Structures (RAS) using Swarm Intelligence based Algorithm

&#x0D; &#x0D; &#x0D; The steady progress in the fields of material science and processing technologies has made multi-layered radar absorbing structures (RAS) an attractive option w.r.t. stealth technologies. They possess the ability to reduce radar cross-section with minimum thickness and is therefore most preferred in airborne applications. As far as their electromagnetic performance is concerned, the sequence of material layers and thickness profile plays a pivotal role. Optimization of these two factors becomes complex in case of availability of large number of potential materials. Commonly used EM simulation software can be employed for the optimization of thickness profile. However, selection of suitable material layer sequence is out of their scope. In this context, a particle swarm optimization (PSO) based algorithm is presented for sequencing of material layers and optimization of thickness profile of multi-layered RAS configurations. The fitness function has been appropriately formulated to achieve maximum power absorption over broad band of frequencies and wide range of incident angles. Further, the efficacy of the algorithm has been demonstrated using a suitable case study.&#x0D; &#x0D; &#x0D;

Shockwave effects in the technology of meat raw material processing

Meat tenderness is recognized as the most important quality characteristic determining consumer acceptability of fresh meat and meat products. Therefore, the development of effective methods for meat tenderization is a topical direction. The review considers the main aspects of the development of shockwave (SW) technology as an alternative method for meat tenderization. The paper analyzes the means of shockwave formation as well as possible mechanisms responsible for meat tenderization caused by shockwave treatment and related to the energy dissipation and mechanical load on the boundary zones of a biological material under processing. The results of the investigations of a shockwave effect on meat tenderness, microbial inactivation, structure and assimilability of muscle protein and other functional and technological properties of a product are presented. The majority of researchers who studied a SW effect on meat tenderization showed different degrees of the improvement in the Warner-Bratzler shear force and increase in sensory scores of meat tenderness. This review shows the main problems linked with commercialization of the meat treatment process using SW based on electrical discharges under water. This method of SW generation is considered safest but infeasible today due to occurrence of restrictions such as damage of packaging materials after treatment, a need to ensure effective SW propagation in a commercial unit and determine optimal treatment parameters in the process of shockwave tenderization. Furthermore, potential possibilities of using shockwave technologies in the food industry are discussed. In particular, shockwave treatment upon extraction is an effective method for extracting juice/ oil/ bioactive components from various plant materials, which can be used as the pretreatment or independent process.

НОВІ ПІДХОДИ ДО ВИВЧЕННЯ ПИТАННЯ «ПРОМЕНЕВІ ТЕХНОЛОГІЇ ОБРОБКИ» ПРИ ВИКЛАДАННІ ДИСЦИПЛІНИ «ОСНОВНІ ПРОЦЕСИ ОБРОБКИ МАТЕРІАЛІВ (МЕТАЛІВ)»

The article considers new approaches in the study of undergraduate students majoring in 014 Secondary Education (Labor Training and Technology) features of beam technologies of metal materials processing, as one of the components of the discipline «Production and processing of structural materials: Basic processes of materials processing (metals)», for due to more efficient composition and presentation of relevant lecture material using a system of multimedia presentations during lecture video conferences in the distance learning. It is shown that students need more careful study of issues related to such types of corpuscular-beam processing of metals and their alloys as electron-beam and ion-beam processing. Peculiarities of material presentation on photon-beam processing of metallic materials are analyzed. When processing this material, students should emphasize that beam methods of processing metals and their alloys are divided into two main groups - corpuscular- beam, when processing is carried out by focused streams (beams) of high-energy particles (electrons, protons, ions), and photonic-(light-)beam, when processing is carried out by focused streams of quanta (photons) of electromagnetic radiation of infrared, visible, ultraviolet or X-ray ranges. The specific energy density of these rays can reach 1010 W/cm2, and the surface heating temperature of materials from them - up to 104 °C, which is accompanied by the processes of melting and evaporation of metals and their alloys in the treatment zone. In most cases, short-pulse is used in beam dimensional processing, ie rays that focus on very small working areas (up to 10-7 cm2) and act for a very short time (10-4-10-13 s) at a frequency of 50-6000 Hz, - they do not act during the emission of evaporated material from the well. In the developed complex of the electronic course of the discipline of lectures-presentations on this topic such kind as ion-beam technology is separately considered - which is a combination of methods of processing metal materials by high-energy ion fluxes (ion doping) and ion lithography, radiation deposition of coatings) as a result of which changes the shape, mechanical, physicochemical, magnetic and electrical properties of the surface layers and even significant parts of the volume of processed metal products. More common technologies of corpuscular-beam processing are electron-beam processing (welding, melting (output of especially pure metals and alloys), drilling, heat treatment of limited zones, micromilling, engraving, annealing, remelting of surface layers, spraying, soldering), using the phenomenon of conversion of kinetic energy of focused beams of accelerated electrons into thermal energy of the surface of processed metallic materials, due to shock braking of electrons moving in vacuum at speeds up to 100 thousand km/s, there is instantaneous heating, melting and evaporation from narrow-diameter 1 μm of the workpiece area. When studying this issue, students should also emphasize that the main photon-beam technologies for processing metals and their alloys are laser technologies for surface (laser surfacing (spraying), alloying, annealing (tempering), hardening without and with a phase transition, surface amortization, engraving, marking, shock hardening, etc.) and for «volume» (cutting, cutting blanks (cutting), punching holes, welding, soldering, etc.) processing of materials.

In-situ enhanced laser absorption in aqueous transition metal salt solution enables high-quality backside wet etching of optical glass by near-infrared lasers

A laser-induced backside wet etching technique using near-infrared laser sources (N-LIBWE) has been proposed for high-quality micromachining of optical glass. Compared with conventional LIBWE using organic dye solutions with high absorption coefficients (∼104–105 cm−1) as the liquid absorbent, the transition metal salt solution used in N-LIBWE shows the absorption coefficient of only 10-1-101 cm−1. Moreover, as we proved in this study, the etching rate of N-LIBWE is independent of the absorptivity of the liquid absorbent. How the etching occurs during N-LIBWE is still controversial. Herein, interface images with a temporal resolution of 4 ns after the start of laser irradiation are captured by a stroboscopic shadowgraphy system. Afterward, the density, pressure, and temperature distribution in the solution are calculated by a physics-based two-dimensional hydrodynamic model to explain the observed interface images. We prove that the localized laser absorption is enhanced with laser irradiation because of the in-situ formation of solid substances. It is the properties of the formed solid products instead of the normal absorption coefficient of the solution that determines the final interface status. We further prove that the formed solid substances in aqueous CuSO4 solutions are primarily amorphous nanoclusters, which benefit the enhancement of laser absorption and tend to attach to the transparent substrates, resulting in the incubation effect in N-LIBWE. Our results provide systematic mechanisms explaining the N-LIBWE process, which also benefit the deep understanding of other liquid-assisted laser materials processing technologies.

Фрагментация и консолидация производственных цепочек в мировой редкоземельной промышленности

The article analyzes the issues of fragmentation and consolidation of value chains using the example of the global rare earth industry. On the one hand, there is a tendency in the world towards specialization of companies at technological stages, which is dictated by the laws of market economy. On the other hand, such fragmentation in the rare earth industry made it possible to monopolize the market and concentrate most of the production stages within one country. Governments of the Western countries are extremely concerned about this problem, but so far only options are being proposed for its solution, which are based on the cooperation of individual participants in the technological chain. The paper discusses consolidation of efforts on the global scale aimed at reducing China's influence on the rare earth metals market, often in spite of the market efficiency. Russia has a significant raw material potential and processing technologies created during the Soviet period, but is not yet able to transform the raw material potential into a high-tech one due to insufficient domestic demand for highly purified rare earth metals

A State-of-the-Art Review on Hemming: A Materials Processing Technology for Mechanical Joints

Abstract Hemming is a material processing technology widely used in major sectors such as automotive and aerospace industries. As a mechanical joining process, hemming is applied to sheet metal components to build structural assemblies. In conventional hemming methods, dies and presses are used by designing product-specific tooling. In recent years, robot technologies have been integrated into this specific process to benefit from the advantages of flexible manufacturing systems. In this paper, a state-of-the-art review of the hemming process is presented based on a literature review. Since there is no background of collected works and systematic reviews, this work summarizes all the details and key points about hemming. This review fulfills the need for compiled knowledge at the right time because of two main reasons. First, there is no review currently on this issue to enlighten both industry and academia. Second, hemming technologies have been enhanced by the leading industrial companies without any contributions of written sources to the literature. In this work, the evolution of hemming technology is given from past to present. Deformation mechanisms in different hemming methods are presented. Effects of process parameters are discussed in terms of product quality, mechanics of materials, and manufacturing aspects. Lastly, recent developments in hemming technologies are given. Despite the availability of alternative joining methods, hemming remains at the forefront of metal joining processes due to its unrivaled simplicity.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

RETRACTED ARTICLE: Machinability study on dry machining of white cast iron by polycrystalline cubic boron nitride inserts

We, the Editors and Publisher of Machining Science and Technology have retracted the following article: Xin Guo, Ling Chen, Wu Zhao, Hao Wan, Huiting Wen & Jinming Zhou (2022) Machinability study on dry machining of white cast iron by polycrystalline cubic boron nitride inserts, Machining Science and Technology, 26:2, 137–159. https://doi.org/10.1080/10910344.2022.2044851 Following publication, the authors requested the withdrawal of this article in 2022 due to conflicting findings with their recent research studies. However, upon further investigation by the Publisher, in collaboration with the Editors, it was found that this article has significant similarities with the following published article which has not been acknowledged appropriately: Ling Chen, Jan-Eric Stahl, Wu Zhao, Jinming Zhou. (2018). Assessment on abrasiveness of high chromium cast iron material on the wear performance of PCBN cutting tools in dry machining, Journal of Materials Processing Technology 255, 110–120. https://doi.org/10.1016/j.jmatprotec.2017.11.054. These unacknowledged similarities are in the form of: text overlaps in the sections “Material preparation”, “Nanoindentation test”, and “Tool wear”, and; reused images included in figures 5 and 6, which are not referenced. Upon query, the corresponding author has not been able to provide a satisfactory explanation for the significant level of overlap. As this is a serious breach of the journal’s editorial policies, we are retracting the article from the journal. The authors disagree with the Publisher’s and Editors’ reasons for retraction. We have been informed in our decision-making by our editorial policies and the COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

Review of Silicon Carbide Processing for Power MOSFET

Owing to the superior properties of silicon carbide (SiC), such as higher breakdown voltage, higher thermal conductivity, higher operating frequency, higher operating temperature, and higher saturation drift velocity, SiC has attracted much attention from researchers and the industry for decades. With the advances in material science and processing technology, many power applications such as new smart energy vehicles, power converters, inverters, and power supplies are being realized using SiC power devices. In particular, SiC MOSFETs are generally chosen to be used as a power device due to their ability to achieve lower on-resistance, reduced switching losses, and high switching speeds than the silicon counterpart and have been commercialized extensively in recent years. A general review of the critical processing steps for manufacturing SiC MOSFETs, types of SiC MOSFETs, and power applications based on SiC power devices are covered in this paper. Additionally, the reliability issues of SiC power MOSFET are also briefly summarized.