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Effect of Ultrasonic Impact on the Microstructure of Welded Joint of 2195 Al–Li Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第4期29卷 367-372页

作者： Qi-Hao Chen san-bao lin Chun-Li Yang Cheng-Lei Fan State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

It is known that an ultrasonic impact during tungsten inert gas welding can refine the grains and improve the mechanical properties of the welded joints of aluminum alloys. However, the influence mechanism of the ultrasonic impact on the microstructures is still unclear. In this research, the effects of the mechanical and ultrasonic impact on the microstructures of the welded joint of 2195 Al-Li alloy are analyzed. It is found that the mechanical impact could not refine the grains, but the ultrasonic impact could refine the grains. The grains become smaller in the weld center with an increase in the ultrasonic amplitude. Possible mechanisms for the grain refinement are discussed. The results show that the small temperature gradient promotes formation of the equiaxed grain and the cavitation promotes heterogeneous nucleation.

关键词： Ultrasound TIG welding Microstructure Al-Li alloy

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Defence Technology（防务技术） 2023年第9期27卷 138-153页

作者： Zeng Liu Cheng-lei Fan Chun-li Yang Zhu Ming san-bao lin Lang-ping Wang State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin150001China Inner Mongolia Metal Material Research Institute Yantai264000China

Ar-N_(2)-O_(2)ternary shielding gas is employed in dissimilar welding between high nitrogen steel and low alloy *** effect of O_(2)and N_(2)is investigated based on the systematical analysis of the metal transfer,nitrogen escape phenomenon,weld appearance,nondestructive detection,nitrogen content distribution,microstructure and mechanical *** are two nitrogen sources of the nitrogen in the weld:high nitrogen base material and shielding *** effect of shielding gas is mainly reflected in these two *** change of the droplet transfer mode affects the fusion ratio,N2in the shielding gas can increase nitrogen content and promote the nitrogen uniform *** addition of 2%O_(2)to Ar matrix can change the metal transfer from globular transfer to spray transfer,high nitrogen base material is thereby dissolved more to the molten pool,making nitrogen content increase,ferrite decrease and the mechanical properties *** applying N2-containing shielding gas,arc stability becomes poor and short-circuiting transfer frequency increases due to the nitrogen escape from droplets and the molten *** of the joints is improved with N_(2)increasing,but internal gas pores are easier to appear because of the poor capacity of low alloy steel to dissolve nitrogen,The generation of pores will greatly reduce the impact resistance.4-8%N2content in shielding gas is recommended in this study considering the integrated properties of the dissimilar welded joint.

关键词： High nitrogen steel Dissimilar steel joints Shielding gas Metal transfer Microstructure Mechanical properties

Effect of Ultrasound on Heterogeneous Nucleation in TIG Welding of Al–Li Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1081-1088页

作者： Qi-Hao Chen san-bao lin Chun-Li Yang Cheng-Lei Fan Hong-Liang Ge State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

The effect of ultrasound on heterogeneous nucleation in a tungsten inert gas （TIG） weld pool of 2195 Al-Li alloy has been investigated by a series of experiments. An ultrasonic vibration was imposed on the surface of base material before turning off the welding arc during the TIG welding implemented at a fixed point. The results suggest that ultrasound could promote heterogeneous nucleation in the TIG weld pool of 2195 Al-Li alloy. The grain around the fusion zone is changed from a column grain to an equiaxed grain after applying the ultrasonic treatment. To study the influencing mechanism of ultrasound on heterogeneous nucleation, further investigations were implemented where the welding arc was turned off after turning off the ultrasonic power. The results show that the equiaxed grain around the fusion zone disappeared gradually with an increase in heat input after turning off the ultrasonic power. It suggests that ultrasound could promote the heterogeneous nucleation particle to nucleate in advance before turning off the welding arc and the crystal nucleus could again be melted with an increase in heat input after turning off the ultrasonic power. Moreover, the effects of the welding current and ultrasonic amplitude on heterogeneous nucleation in the weld pool of 2195 Al-Li alloy were also investigated. Possible influencing mechanism of the welding current and ultrasonic amplitude on heterogeneous nucleation was discussed.

关键词： Ultrasound TIG welding Grain Al-Li alloy

Microstructure and Corrosion Behavior of Friction Stir Welded Al Alloy Coated by In Situ Shot-Peening-Assisted Cold Spray

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Acta Metallurgica Sinica(English Letters) 2020年第1期33卷 172-182页

作者： Hua Zhang Chang-Yu Zhao Qi-Long Guo Rui-Sheng Yang Li-Yuan Liu san-bao lin School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Beijing Institute of Astronautical Systems and Engineering Beijing 100076China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

To improve the corrosion resistance of friction stir welded(FSW)joints,in situ shot-peening-assisted cold spray coating was applied to the surface of FSW *** microstructure and corrosion behavior of the coatings were *** results showed that a dense coating was obtained by cold spraying ***,the use of in situ shot-peeningassisted technology significantly reduced the porosity of the coating,which has a positive impact on the microstructure and the mechanical *** corrosion tests showed that the coating aff ected positively on the corrosion *** the coated surface,the craters caused by shot-peening particles were corroded in the form of exfoliation corrosion,while the exposed particles were corroded in the form of intercrystalline *** work provides a new approach to the corrosion protection of FSW joints.

关键词： Aluminum alloy coating Cold spray Friction stir welding In situ shot-peening Intergranular corrosion

Gas metal arc welding of high nitrogen stainless steel with AreN_(2)-O_(2)ternary shielding gas

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Defence Technology（防务技术） 2021年第3期17卷 923-931页

作者： Zeng Liu Cheng-lei Fan Zhu Ming Chao Chen Ang Liu Chun-li Yang san-bao lin Lang-ping Wang State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin150001China Inner Mongolia Metal Material Research Institute BaotouChina

High nitrogen stainless steel with nitrogen content of 0.75%was welded by gas metal arc welding with Ar-N_(2)-O_(2)ternary shielding *** effect of the ternary shielding gas on the retention and improvement of nitrogen content in the weld was *** test was conducted first to compare the ability of O_(2)and CO_(2)in prompting nitrogen *** nitrogen content of the surfacing metal with O_(2)is slightly higher than CO_(2).And then AreN_(2)-O_(2)shielding gas was applied to weld high nitrogen stainless *** using N_(2)-containing shielding gas,the nitrogen content of the weld was improved by 0.1 wt%.As N_(2)continued to increase,the increment of nitrogen content was not obvious,but the ferrite decreased from the top to the *** the proportion of N_(2)reached 20%,a full austenitic weld was obtained and the tensile strength was improved by 8.7%.Combined with the results of surfacing test and welding test,it is concluded that the main effect of N_(2)is to inhibit the escape of nitrogen and suppress the nitrogen diffusion from bottom to the top in the molten pool.

关键词： High nitrogen stainless steel AreN2-O2 shielding gas Action mechanism

CaH2-promoted activity of Ni-carbonate interface for CO2 methanation

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Journal of Energy Chemistry 2025年第1期100卷 522-532页

作者： Jin-Peng Wang Guo-Cui Mao Hui-lin Jiang bao-Xia Dong Yun-Lei Teng School of Chemistry and Chemical Engineering Yangzhou University

Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic *** interface between transition metal and metal carbonate exhibits a dynamic equilibrium during the CO2hydrogenation reaction,involving surface carbonate hydrogenation and ***,there have been few reports on engineering the activity of the interface between transition metal and alkaline earth metal carbonate for catalytic *** work demonstrated that the incorporation of CaH2in Ni/CaCO3enhances the CO2methanation activity of the *** CO2conversion for Ni/CaH2-CaCO3reached 68.5%at 400°C,which was much higher than that of the Ni/CaCO3（31.6%） and Ni/CaH2-CaO （42.4%） ***,the Ni/CaH2-CaCO3catalysts remained stable during the stability test for 24 h at 400°C and 8 *** research revealed that CaH2played a crucial role in promoting the activity of the Ni-carbonate interface for ***2could modify the electronic structure of Ni and tune the structural properties of CaCO3to generate medium basic sites （OH groups）,which are favorable for the activation of H2and ***-situ Fourier transform infrared spectroscopy （FTIR） analysis combined with density functional theory calculations demonstrated that CO2activation occurs at the hydroxyl group （OH） on the CaH2-modified Ni-carbonate surface,leading to the formation of CO3H****,our study has confirmed that CO2methanation over the Ni/CaH2-CaCO3catalysts proceeds via the formate pathway.

关键词： CO 2 methanation Metal hydride Ni catalysts Carbonate Metal-carbonate interface

Transient thermal cracking associated with non-classical heat conduction in cylindrical coordinate system

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Acta Mechanica Sinica 2013年第2期29卷 211-218页

作者： bao-lin Wang Graduate School at Shenzhen Harbin Institute of Technology

This paper studies the fracture behavior of a thermoelastic cylinder subjected to a sudden temperature change on its outer surface within the framework of non-classical heat *** heat conduction equation is solved by separation of variable *** form solution for the temperature field and the associated thermal stress are *** critical parameter governing the level of the transient thermal stress is *** expression for the transient stress intensity factor is obtained for a crack in the *** difference between the non-classical solutions and the classical solution are *** is found that the traditional classical heat conduction considerably underestimates the transient thermal stress and thermal stress intensity factor.

关键词： Thermal stresses·Fracture mechanics·Nonclassical heat conduction

Promoting catalytic ozonation of phenol over graphene through nitrogenation and Co_3O_4 compositing

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Journal of Environmental Sciences 2016年第12期28卷 38-48页

作者： Qi bao Kwan san Hui Jenq Gong Duh Department of Materials Science and Engineering Taiwan Tsing Hua University Department of Systems Engineering & Engineering Management City University of Hong Kong Department of Mechanical Engineering Hanyang University

Catalytic ozonation is progressively becoming an attractive technique for quick water purification but efficient and stable catalysts remains elusive. Here we solvothermally synthesized highly-dispersed Co3O4 nanocrystals over microscale nitrogen-doping graphene （NG） nanosheets and tested it as a synthetic catalyst in the ozonation of phenol in aqueous solutions. Transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectra and X-ray photoelectron spectroscopy were used to determine its morphology, crystallinity, elemental composition and molecular bonds, respectively. The comparative experiments confirmed the highest catalytic activity and oxidation degree （AOSC） of Co3O4/NG among four nanocomposites （G, NG, Co3O4/G, and Co3OJNG）. Co3O4/NG also has exhibited the highest degradation rate： complete conversion of a near-saturated concentration of phenol （941.1 mg/L） was achieved within 30 min under ambient conditions with only a small dosage of Co3O4/NG （50 mg/L） and ozone （4 mg/L, flow rate： 0.5 L/min）. It also resulted in 34.6% chemical oxygen demand （CODcr） and 24.2% total organic carbon （TOC） reduction. In this work, graphene nanosheets not only functioned as a support for Co3O4 nanocrystals but also functioned as a co-catalyst for the enhancement in phenol removal efficiency. The surface nitridation and Co3O4 modification treatment further improved the removal rate of the phenol pollutants and brought in the higher oxidation degree. Our finding may open new perspectives for pursuing exceptional activity for catalytic ozonation reaction.

关键词： Water treatment Graphene Nanocatalysts Phenol

Mechanism of action of linggui Zhugan Decoction in treating non-alcoholic fatty liver disease using untargeted metabolomics approach

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Traditional Medicine Research 2025年第2期10卷 65-76页

作者： Huan Pei Ren-lin Li Xin-Ran Song Qian-Qian Wan Yu-Ming Wang Han-Zhou Li Wei-Quan Xu Jia-bao Liao Wei-Bo Wen Jing Miao Huan-Tian Cui School of Basic Medicine Yunnan University of Chinese MedicineKunming 650599China School Clinical Medical College Yunnan University of Chinese MedicineKunming 650599China First School of Clinical Medicine Yunnan University of Chinese MedicineKunming 650599China School of Integrative Chinese and Western Medicine Tianjin University of Traditional Chinese MedicineTianjin 301617China Department of Pharmacy Tianjin Second People's HospitalTianjin 300192China

Background:Non-alcoholic fatty liver disease(NAFLD)is a liver disorder characterized by the accumulation and degeneration of fat in the liver cells,a condition that may further deteriorate and lead to cirrhosis and liver *** studies showed that metabolic dysfunction can promote NAFLD *** Zhugan Decoction(LGZGD)has therapeutic effects on *** mechanism of LGZGD still remains *** study was to examine the impact of LGZGD on the metabolic processes involved in the development of ***:A mice model of NAFLD was treated with *** therapeutic potential of LGZGD was evaluated by assessing the activity of transaminases,lipids levels of blood,and pathological changes in the liver of the mice model of ***,this study also evaluated the influence of LGZGD on liver inflammation and oxidative ***:The results of untargeted metabolomics analysis showed that LGZGD reduced the disordered lipid metabolism in NAFLD *** improved the oxidative stress and also reduced the levels of pro-inflammatory cytokines in the *** metabolomics analysis of liver samples revealed that LGZGD treatment improved metabolic disorders,including alanine,aspartate,glutamate,glycerophospholipid metabolism,and citrate *** RT-qPCR and Western blot results showed that LGZGD could regulate the expression of key enzymes in the metabolic pathway of the citrate cycle,including ATP-citrate lyase(ACLY),alanine-glyoxylate aminotransferase-2(AGXT2),phosphatidylethanolamine N-methyltransferase(PEMT),and succinate dehydrogenase(SDH).Conclusion:We found that LGZGD can treat NAFLD by reducing inflammatory responses,inhibiting oxidative stress,regulating alanine,aspartate,glutamate,and glycerophospholipid metabolism,and citrate cycle pathways.

关键词： NAFLD LGZGD untargeted metabolomics glycerophospholipid metabolism citrate cycle