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Journal of Wuhan University of Technology(Materials Science) 2023年第4期38卷 759-765页

作者：赵东升 JING Qiang SUN Jianwei 张金咏 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

The Si_(3)N_(4)/SiC gradient material with a gradient composition structure was prepared by a hot pressing sintering.The sinterability,distribution of residual stress and the effect of residual stress on mechanical properties of Si_(3)N_(4)/SiC gradient materials were studied.The research results show that,at 1750℃,Si_(3)N_(4)/SiC gradient materials with different ratios can achieve co-sintering,and the overall relative density of the sample reaches 98.5%.Interestingly,the flexural strength of Si_(3)N_(4)/SiC gradient material is related to its loading surface.The flexural strength of SiC as the loading surface is about 35%higher than that of Si_(3)N_(4)as the loading surface.The analysis of the residual stress of the material in the gradient structure shows that the gradient stress distribution between the two phases is a vital factor affecting the mechanical properties of the material.With the increase of SiC content in the gradient direction,the fracture toughness of each layer of Si_(3)N_(4)/SiC gradient materials gradually decreases.The surface hardness of the pure SiC side is lower than that reported in other literature.

关键词： Si_(3)N_(4) SiC gradient material residual stress mechanical properties

residual stress with asymmetric spray quenching for thick aluminum alloy plates

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International Journal of Minerals,Metallurgy and Materials 2023年第11期30卷 2200-2211页

作者： Ning Fan Zhihui Li Yanan Li Xiwu Li Yongan Zhang Baiqing Xiong State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

Solution and quenching heat treatments are generally carried out in a roller hearth furnace for large-scale thick aluminum alloy plates.However,the asymmetric or uneven spray water flow rate is inevitable under industrial production conditions,which leads to an asymmetric residual stress distribution.The spray quenching treatment was conducted on self-designed spray equipment,and the residual stress along the thickness direction was measured by a layer removal method based on deflections.Under the asymmetric spray quenching condition,the subsurface stress of the high-flow rate surface was lower than that of the low-flow rate surface,and the difference between the two subsurface stresses increased with the increase in the difference in water flow rates.The subsurface stress underneath the surface with a water flow rate of 0.60 m^(3)/h was 15.38 MPa less than that of 0.15 m^(3)/h.The simulated residual stress by finite element(FE)method of the high heat transfer coefficient(HTC)surface was less than that of the low HTC surface,which is consistent with the experimental results.The FE model can be used to analyze the strain and stress evolution and predict the quenched stress magnitude and distribution.

关键词： aluminum alloy spray quenching residual stress layer removal method finite element method

residual stress analysis of multi-pass cold spinning process

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Chinese Journal of Aeronautics 2022年第3期35卷 259-271页

作者： Zixuan LI Xuedao SHU Faculty of Mechanical Engineering&Mechanics Ningbo UniversityNingbo 315211China Zhejiang Provincial Key Laboratory of Part Rolling Technology Ningbo UniversityNingbo 315211China

Uncontrolled residual stresses have significant effects on the service time and defects of the spun parts.Nowadays,X-Ray Diffraction(XRD)method has been widely used in the residual stress measurement of industry products with different forming processes.The calculated residual stress is usually obtained from the data fitting slope of strain and angle with Ordinary Least Squares(OLS)method.But this fitting method is not always suitable for the big fluctuant data.In this paper,the Weighted Least Square(WLS)method is used for the data fitting and compared with the OLS method.The nickel-based superalloy GH3030 and iron-based superalloy GH1140 are applied in the multi-pass cold spinning experiments.The residual stress distributions of normal,potential crack and wrinkle workpieces are discussed with the grain structure.The results show that WLS method has better goodness of fit compared with OLS method.The residual stress distributions have special relationship with potential crack,wrinkle workpiece and grain structure.

关键词： Cold spinning process Data fitting Grain structure Potential crack residual stress Weighted least square method

residual stress measurement and analysis of siliceous slate-containing quartz veins

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International Journal of Minerals,Metallurgy and Materials 2023年第12期30卷 2310-2320页

作者： Tao Wang Weiwei Ye Yemeng Tong Naisheng Jiang Liyuan Liu School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Strata Intelligent Control and Green Mining Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China

Engineering geological disasters such as rockburst have always been a critical factor affecting the safety of coal mine production.Thus,residual stress is considered a feasible method to explain these geomechanical phenomena.In this study,electron backscatter diffraction(EBSD)and optical microscopy were used to characterize the rock microcosm.A measuring area that met the requirements of X-ray diffraction(XRD)residual stress measurement was determined to account for the mechanism of rock residual stress.Then,the residual stress of a siliceous slate-containing quartz vein was measured and calculated using the sin^(2) ϕ method equipped with an X-ray diffractometer.Analysis of microscopic test results showed homogeneous areas with small particles within the millimeter range,meeting the requirements of XRD stress measurement statistics.Quartz was determined as the calibration mineral for slate samples containing quartz veins.The diffraction patterns of the(324)crystal plane were obtained under different ϕ and φ.The deviation direction of the diffraction peaks was consistent,indicating that the sample tested had residual stress.In addition,the principal residual stress within the quartz vein measured by XRD was compressive,ranging from 10 to 33 MPa.The maximum principal stress was parallel to the vein trend,whereas the minimum principal stress was perpendicular to the vein trend.Furthermore,the content of the low-angle boundary and twin boundary in the quartz veins was relatively high,which enhances the resistance of the rock mass to deformation and promotes the easy formation of strain concentrations,thereby resulting in residual stress.The proposed method for measuring residual stress can serve as a reference for subsequent observation and related research on residual stress in different types of rocks.

关键词： residual stress siliceous sand rock microstructure X-ray diffraction electron backscatter diffraction

residual-stress relaxation mechanism and model description of 5052H32 Al alloy spun ellipsoidal heads during annealing treatment

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Advances in Manufacturing 2022年第1期10卷 87-100页

作者： Yong-Cheng Lin Jiang-Shan Zhu Jia-Yang Chen Jun-Quan Wang School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083People’s Republic of China

Marginal-restraint mandrel-free spinning is an advanced technology for manufacturing ellipsoidal heads with large diameter-thickness ratios.Nevertheless,the spinning-induced residual stress,which greatly influences the in-service performance of spun heads,should be removed.In this study,the effects of annealing on the residual-stress relaxation behavior of 5052H32 aluminum alloy spun heads were investigated.It is found that the residual stress first rapidly decreases and then remains steady with the increase in annealing time at the tested annealing temperatures.The relaxation of the residual stress becomes increasingly obvious with the increase in annealing temperature.When the annealing temperature is less than 220℃,there are no obvious changes in grain size.Moreover,the spinning-induced dislocations are consumed by the static recovery behavior,which decreases the residual stress during annealing.When the annealing temperature is approximately 300℃,the broken grains transform into equiaxed grains.In addition,static recrystallization and recovery behaviors occur simultaneously to promote the relaxation of the residual stress.Considering the different stress relaxation mechanisms,a model based on the Zener-Wert-Avrami equation was established to predict the residual-stress relaxation behavior.Finally,the optimized annealing temperature and time were approximately 300C and 30 min,respectively.

关键词： Spinning residual stress Annealing treatment Microstructure evolution Relaxation mechanism

residual stress indentation model based on material equivalence

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Chinese Journal of Aeronautics 2022年第8期35卷 304-313页

作者： Xiaokun LIU Lixun CAI Hui CHEN Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Changsha University of Science&TechnologyChangsha 410114China

A novel residual stress indentation model for conical indentation loading is proposed to describe the relationship between the residual stress,material constitutive parameters,load,and displacement for materials with a uniaxial constitutive relationship that obeys Hollomon’s power law(H-law).The novel model was established based on the principle that the equivalent material without residual stress corresponds to the original material with residual stress,conical indentation theoretical model based on energy density equivalence,and an assumed power-law relationship between the dimensionless residual stress and relative difference of the yield stresses of the equivalent material and original material.Sixty imaginary H-law materials with ten equibiaxial and ten uniaxial residual stresses were investigated by Finite Element Analysis(FEA).The residual stresses predicted by the novel model from the indentation load–displacement curves simulated for the imaginary materials are in close agreement with those applied by the FEA.Finally,indentation tests for Cr12Mo V steel,45 steel,and 6061-T6511 aluminum alloy were carried out on their specimens without residual stress and their bending specimens with equibiaxial and uniaxial residual stresses.The residual stresses predicted by the novel model according to the indentation load–displacement test curves are in good agreement with those applied by the tests.

关键词： Conical indentation Equivalent material Finite element analysis residual stress Theoretical model

residual stress and precipitation of Mg-5Zn-3.5Sn-1Mn-0.5Ca-0.5Cu alloy with different quenching rates

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Journal of Magnesium and Alloys 2021年第2期9卷 604-612页

作者： Cong Wang Tianjiao Luo Yunteng Liu Qiuyan Huang Yuansheng Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Shandong Key Laboratory for High Strength Lightweight Metallic Materials Advanced Materials InstituteShandong Academy of SciencesShandong 250014China

The effect of the quenching rate after solution treatment on the residual stress and precipitation behavior of a high strength Mg-5 Zn-3.5 Sn-1 Mn-0.5 Ca-0.5 Cu plate is studied.The simulation results show decreasing temperature gradient in the plate with decreasing quenching rate,which leads to weakened inhomogeneous plastic deformation and decreased residual stress.No dynamic precipitation on the grain boundary happens after either cold water cooling or air cooling,however,air cooling leads to dynamic precipitation of Mg-Zn phase on Mn particles around which a low-density precipitate zone develops after aging treatment.Moreover,the fine and densely distributed Mg-Zn precipitates observed after aging treatment of the cold water cooled alloy are replaced by coarse precipitates with low density for the air cooled alloy.Both the low-density precipitate zone near Mn particles and the coarsening of precipitates are the source of the decrease in hardness and tensile properties of the air cooled alloy.The residual stress drops faster than the hardness with decreasing quenching rate,which makes it possible to lower the residual stress without sacrificing too much age-hardening ability of the alloy.

关键词： Mg-5Zn-3.5Sn-1Mn-0.5Ca-0.5Cu alloy Solution treatment Quenching rate residual stress Precipitation Age-hardening

residual stress variation in SiC_(f)/SiC composite during heat treatment and its effects on mechanical behavior

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Journal of Advanced Ceramics 2020年第5期9卷 567-575页

作者： Xiaowu CHEN Guofeng CHENG Junmin ZHANG Feiyu GUO Haijun ZHOU Chunjin LIAO Hongda WANG Xiangyu ZHANG Shaoming DONG State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Analysis and Testing Center for Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China School of Physical Science and Technology ShanghaiTech UniversityShanghai 200031China

residual stress originated from thermal expansion mismatch determines the mechanical properties of ceramic matrix composites(CMCs).Here,continuous SiC fiber reinforced SiC matrix(SiC_(f)/SiC)composites were fabricated by nano-infiltration and transient eutectic-phase(NITE)method,and the residual stress of the composites was investigated using high-temperature Raman spectrometer.With temperature increasing from room temperature to 1400℃,the residual stresses of the matrix and the fiber decrease from 1.29 to 0.62 GPa and from 0.84 to 0.55 GPa in compression respectively,while that of the interphase decreases from 0.16 to 0.10 GPa in tension.The variation of residual stress shows little effect on the tensile strength of the composites,while causes a slight decrease in the tensile strain.The suppression of fiber/matrix debonding and fiber pulling-out caused by the residual stress reduction in the interphase is responsible for the decreasing tensile strain.This work can open up new alternatives for residual stress analysis in CMCs.

关键词： residual stress nano-powder infiltration and transient eutectoid(NITE) Raman spectroscopy mechanical properties

residual stress Relaxation of Thin‑walled Long Stringer Made of Aluminum Alloy 7050‑T7451 under Transportation Vibration

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Chinese Journal of Mechanical Engineering 2020年第3期33卷 150-159页

作者： Yinfei Yang Lu Jin Jixing Du Liang Li Wei Yang Nanjing University of Aeronautics and Astronautics Nanjing 210016China Shenyang Aircraft Corporation Shenyang 110034China.

Thin-walled long stringer made of aluminum alloy 7050-T7451 is prone to deformation during transportation,so a research of residual stress relaxation was launched in this paper.The transport resonance stress of long stringer was analyzed based on the power spectral density of road transport acceleration.The residual stress relaxation experiment of aluminum alloy 7050-T7451 under different equivalent stress levels was designed and carried out.According to the amount of residual stress relaxation in the experiment,an analytical model was established with the equivalent stress level coefficient.The deflection range of long stringer was evaluated under different damping ratios.The results show that when the equivalent stress exceeds 0.8σ0.2,the residual stress relaxation of the thin-walled samples occurs.The residual stress relaxation increases linearly with the equivalent stress,which is logarithmically related to the loading cycle.The deformation caused by residual stress relaxation of the long stringer is proportional to the square of the length and the bending moment caused by stress rebalance,and inversely proportional to the moment of inertia of the structure.As the damping ratio decreases from 0.03 to 0.01,the total deflection of the long stringer increases from 0 to above 1.55 mm.

关键词： Aluminum alloy 7050-T7451 Large thin-walled part Transportation process residual stress Structural deformation

residual stress distribution as a function of depth in graphite/copper brazing joints via X-ray diffraction

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Journal of Materials Science & Technology 2019年第11期35卷 2470-2476页

作者： Chun Li Xiaoqing Si Jian Cao Junlei Qi Zhibo Dong Jicai Feng State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

The residual stress distributions as a function of depth in three different graphite/copper brazing joints:with no interlayer,with a copper interlayer and with a niobium interlayer are measured via X-ray diffraction by transmission geometry.The residual stress in all the joints is found to be generally compressive and increasing from the surface to the interface.Copper and niobium interlayers are both effective in alleviating the residual stress in the joint and the stress value in the joint with a niobium interlayer appearing to be the lowest.The strength of the joint is demonstrated to be closely related to the residual stress and the fracture position of the joint corresponds well with the highest residual stress.

关键词： Brazing residual stress XRD Graphite Copper