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Surface Integrity of Inconel 738LC Parts Manufactured by Selective Laser Melting Followed by High-speed Milling

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 65-79页

作者： Guanhui Ren Sai Guo bi zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen518055China Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials Shenzhen518055China Research and Development Department Shenzhen Xinjinquan Precision Techonology Co.Ltd.Shenzhen518055China School of Mechanical Engineering Shandong UniversityJinan250061China

This study is concerned with the surface integrity of Inconel 738LC parts manufactured by selective laser melting(SLM)followed by high-speed milling(HSM).In the investigation process of surface integrity,the study employs ultradepth three-dimensional microscopy,laser scanning confocal microscopy,scanning electron microscopy,electron backscatter diffractometry,and energy dispersive spectroscopy to characterize the evolution of material microstructure,work hardening,residual stress coupling,and anisotropic effect of the building direction on surface integrity of the *** results show that SLM/HSM hybrid manufacturing can be an effective method to obtain better surface quality with a thinner machining metamorphic ***-speed machining is adopted to reduce cutting force and suppress machining heat,which is an effective way to produce better surface mechanical properties during the SLM/HSM hybrid manufacturing *** general,high-speed milling of the SLM-built Inconel 738LC samples offers better surface integrity,compared to simplex additive manufacturing or casting.

关键词： Surface integrity Inconel 738LC Selective laser melting High-speed milling

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 224-239页

作者： Sai Guo Guanhui Ren bi zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhenGuangdongChina State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongChina

New materials and manufacturing technologies require applicable non-destructive techniques for quality assurance so as to achieve better *** study comprehensively investigated the effect of influencing factors includ-ing excitation frequency,lift-off distance,defect depth and size,residual heat,and surface roughness on the defect EC signals of an Inconel 738LC alloy produced by selective laser melting(SLM).The experimental investigations recorded the impedance amplitude and phase angle of EC signals for each defect to explore the feasibility of detecting sub-surface defects by merely analyzing these two key ***,this study revealed preliminary qualitative and roughly quantitative relationships between influencing factors and corresponding EC signals,which provided a prac-tical reference on how to quantitively inspect subsurface defects using eddy current testing(ECT)on SLMed parts,and also made solid progress toward on-line ECT in additive/subtractive hybrid manufacturing(ASHM)for fabricating SLMed parts with enhanced quality and better performance.

关键词： Eddy current testing Subsurface defect Additive/subtractive hybrid manufacturing Selective laser melting Inconel 738LC alloy

A self-tuning control method for Wiener nonlinear systems and its application to process control problems

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Chinese Journal of Chemical Engineering 2017年第2期25卷 193-201页

作者： Ping Yuan bi zhang Zhizhong Mao College of Information Science & Engineering Northeastern University Shenyang 110819 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang 110819 China

Many chemical processes can be modeled as Wiener models, which consist of a linear dynamic subsystem followed by a static nonlinear block. In this paper, an effective discrete-time adaptive control method is proposed for Wiener nonlinear systems with uncertainties. The parameterization model is derived based on the inverse of the nonlinear function block. The adaptive control method is motivated by self-tuning control and is derived from a modified Clarke criterion function, which considers both tracking properties and control efforts. The uncertain parameters are updated by a recursive least squares algorithm and the control law exhibits an explicit form. The closed-loop system stability properties are discussed. To demonstrate the effectiveness of the obtained results, two groups of simulation examples including an application to composition control in a continuously stirred tank reactor(CSTR) system are studied.

关键词： Wiener systemsAdaptive controlUncertaintiesStabilityCSTR

Defect Formation Mechanisms in Selective Laser Melting:A Review

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 515-527页

作者： bi zhang Yongtao Li Qian Bai Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Department of Mechanical Engineering University of Connecticut

Defect formation is a common problem in selective laser melting （SLM）. This paper provides a review of defect formation mechanisms in SLM. It sum- marizes the recent research outcomes on defect findings and classification, analyzes formation mechanisms of the common defects, such as porosities, incomplete fusion holes, and cracks. The paper discusses the effect of the process parameters on defect formation and the impact of defect formation on the mechanical properties of a fabri- cated part. Based on the discussion, the paper proposes strategies for defect suppression and control in SLM.

关键词： Selective laser melting Process parameters -Defect Mechanical properties

Corrosion behavior of nickel-based 718 alloy determined by in situ electrochemical methods at different partial pressures of H2S in 25 wt% NaCl solution at 150℃

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Rare Metals 2019年第9期38卷 855-863页

作者： Yu-bi zhang Xiao-Liang Yang An Tang School of Mechanical Engineering Henan University of EngineeringZhengzhou 451191China Chongqing Materials Research Institute Co. LtdChonging 400707China

The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for 168 *** tested results show that anodic reactions are controlled alternately by the diffusion mostly,then both charge transfer and diffusion and finally charge transfer mainly with the increment of PH2 *** corrosive products are composed of sulfides and oxides of Ni,Cr and Fe with double layers for PH2 S of 5.1 and 13.0 MPa and three layers for PH2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope(SEM)and electron probe microanalysis(EPMA)*** inner oxides layer plays a critical role in anti-corrosion in a wet H2 S environment at high temperature and pressure.

关键词： Nickel-based 718 alloy Corrosion electrochemistry Polarization Passive film

Methods for Detection of Subsurface Damage:A Review

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 23-36页

作者： Jing-fei Yin Qian Bai bi zhang Key Laboratory for Precision and Non-traditional Machining of Ministry of Education Dalian University of Technology Department of Mechanical and Energy Engineering South University of Science and Technology

Subsurface damage is easily induced in machining of hard and brittle materials because of their particular mechani?cal and physical properties. It is detrimental to the strength,performance and lifetime of a machined part. To manu?facture a high quality part,it is necessary to detect and remove the machining induced subsurface damage by the subsequent processes. However,subsurface damage is often covered with a smearing layer generated in a machining process,it is rather di cult to directly observe and detect by optical microscopy. An e cient detection of subsur?face damage directly leads to quality improvement and time saving for machining of hard and brittle materials. This paper presents a review of the methods for detection of subsurface damage,both destructive and non?destructive. Although more reliable,destructive methods are typically time?consuming and confined to local damage infor?mation. Non?destructive methods usually su er from uncertainty factors,but may provide global information on subsurface damage distribution. These methods are promising because they can provide a capacity of rapid scan and detection of subsurface damage in spatial distribution.

关键词： Subsurface damage Hard and brittle material Taper polishing Measurement Laser scattering

Tripartite motif-containing protein 11(TRIM11):a novel weapon against Alzheimer’s disease

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Signal Transduction and Targeted Therapy 2024年第2期9卷 339-340页

作者： Yichu Fu bi zhang Jianfeng Liu College of Life Science and Technology Key Laboratory of Molecular Biophysics of MOEHuazhong University of Science and TechnologyWuhanHubei 430074China

In a recent study published in Science,zhang et *** that tripartite motif-containing(TRIM)protein 11(TRIM11)exhibited strong inhibition on tau aggregation,which is a pathological characteristic of tauopathies including Alzheimer’s disease(AD).1 This makes TRIM11 a promising novel target for the treatment of AD and other tauopathies.

关键词： Alzheimer tau TRIM

A Micro-coupling for Micro Mechanical Systems

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 571-578页

作者： LI Wei ZHOU Zhixiong zhang bi XIAO Yunya College of Mechanical and Vehicle Engineering Hunan University School of Engineering University of Connecticut

The error motions of micro mechanical systems, such as micro-spindles, increase with the increasing of the rotational speed, which not only decreases the rotational accuracy, but also promotes instability and limits the maximum operational speed. One effective way to deal with it is to use micro-flexible couplings between the drive and driven shafts so as to reduce error motions of the driven shaft. But the conventional couplings, such as diaphragm couplings, elastomeric couplings, bellows couplings, and grooved couplings, etc, cannot be directly used because of their large and complicated structures. This study presents a novel micro-coupling that consists of a flexible coupling and a shape memory alloy（SMA）-based clamp for micro mechanical systems. It is monolithic and can be directly machined from a shaft. The study performs design optimization and provides manufacturing considerations, including thermo-mechanical training of the SMA ring for the desired Two-Way-Shape-Memory effect（TWSMe）. A prototype micro-coupling and a prototype micro-spindle using the proposed coupling are fabricated and tested. The testing results show that the prototype micro-coupling can bear a torque of above 5 N · mm and an axial force of 8.5 N and be fitted with an SMA ring for clamping action at room temperature（15 ℃） and unclamping action below –5 ℃. At the same time, the prototype micro-coupling can work at a rotational speed of above 200 kr/min with the application to a high-speed precision micro-spindle. Moreover, the radial runout error of the artifact, as a substitute for the micro-tool, is less than 3 μm while that of turbine shaft is above 7 μm. It can be concluded that the micro-coupling successfully accommodates misalignment errors of the prototype micro-spindle. This research proposes a micro-coupling which is featured with an SMA ring, and it is designed to clamp two shafts, and has smooth transmission, simple assembly, compact structure, zero-maintenance and balanced motio

关键词： coupling clamp shape memory alloy thermo-mechanical training micro-spindle

Additive Manufacturing of Ceramic Structures by Laser Engineered Net Shaping

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1117-1122页

作者： NIU Fangyong WU Dongjiang MA Guangyi zhang bi Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Department of Mechanical Engineering University of Connecticut

Ceramic is an important material with outstanding physical properties whereas impurities and porosities generated by traditional manufacturing methods limits its further industrial applications. In order to solve this problem, direct fabrication of Al2O3 ceramic structures is conducted by laser engineered net shaping system and pure ceramic powders. Grain refinement strengthening method by doping Zr O2 and dispersion strengthening method by doping Si C are proposed to suppress cracks in fabricating Al2O3 structure. Phase compositions, microstructures as well as mechanical properties of fabricated specimens are then analyzed. The results show that the proposed two methods are effective in suppressing cracks and structures of single-bead wall, arc and cylinder ring are successfully deposited. Stable phase of α-Al2O3 and t-Zr O2 are obtained in the fabricated specimens. Micro-hardness higher than 1700 HV are also achieved for both Al2O3 and Al2O3/Zr O2, which are resulted from fine directional crystals generated by the melting-solidification process. Results presented indicate that additive manufacturing is a very attractive technique for the production of high-performance ceramic structures in a single step.

关键词： lasers net shaping alumina ceramics additive manufacturing