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Fatigue Crack Initiation and Propagation Dominated by Crystallographic Factors in TiB/near α-Ti Composite

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 763-776页

作者： Fanchao Meng Rui Zhang Shuai Wang Fengbo Sun run chen Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Discontinuously reinforced titanium matrix composites(DRTMCs)with a network structure have been extensively researched due to their superior combination of strength and ***,their fatigue performance has remained *** order to elucidate the fatigue behavior of DRTMCs,a tension-tension fatigue test was performed on a TiB/nearα-Ti composite with network *** results showed that the variability of fatigue lifetime increased as the stress level *** analysis indicated that fatigue crack initiation was associated with facet formation,while the subsequent propagation was hindered by the network structure comprising TiB whiskers and *** characterization further revealed that facets formed due to a combination of shear and normal *** reduction in fatigue lifetime was attributed to an increase in the effective slip length,which was influenced by the orientation of grains near the crack-initiation sites toward basal slip in the life-limiting *** in situ observation suggested that the crack initiation was facilitated by both basal and prismatic slip ofα-Ti as well as fracture of *** propagation was found to be associated with basal and prismatic slip systems with high Schmid factors,regardless of whether the crack was intergranular or intragranular.

关键词： Titanium matrix composite TiBw Fatigue lifetime variability Crack initiation Crack propagation

Hot deformation behavior and microstructure evolution of GH3536-TiB_(2) composites fabricated by powder metallurgy

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Science China(Technological Sciences) 2024年第7期67卷 2107-2124页

作者： ZHOU ShiPeng WANG Shuai HUANG LuJun ZHANG Rui chen Xin MENG FanChao chen run SUN FengBo WANG CunYu GENG Lin School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

The hot deformation behavior and microstructure evolution of GH3536-TiB2composites fabricated by powder metallurgy(PM)were examined in the temperature range of 950–1150℃ and strain rate range of 0.001–1 s^(-1). The hot compression stress-strain curves and the constitutive equation were obtained. In addition, the hot processing map was drawn, which indicated that the appropriate hot working window was 950–1050℃/0.001–0.1 s^(-1)and 1050–1100℃/0.001–0.01 s^(-1). The microstructure analysis showed that the splitting and spheroidization of M3B2led to a decrease in size and volume fraction at 950–1100℃. At 1150℃,the eutectic microstructure of M_(3)B_(2)+ γ was formed due to the dissolution of M_(3)B_(2), which caused macroscopic cracking of the deformed sample. Additionally, the deformation temperature and the strain rate had little effect on the size and volume fraction of M_(3)B_(2). Besides, discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX) were found in the deformed microstructure, while the former was dominant. Within the test range of this work, the dynamic recrystallization(DRX) fraction of the deformed composites was high due to the bulging nucleation of numerous interfaces. The DRX grain size increased with increasing deformation temperature or decreasing strain rate. Texture analysis showed that the deformation texture of //compression direction RD existed in the matrix when the deformation temperature was below 1100℃, and the texture type became //RD at 1100℃. Additionally, it was also found that the //RD texture was formed in M3B2under the strain rates of 0.1 and 0.01 s^(-1).

关键词： GH3536 alloy matrix composites powder metallurgy hot deformation behavior microstructure evolution

A Hf-doped dual-phase high-entropy alloy: phase evolution and wear features

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Rare Metals 2024年第1期43卷 324-333页

作者： Hao Ren Rui-run chen Xue-Feng Gao Tong Liu Gang Qin Yu-Lung Chiu Shi-Ping Wu Jing-Jie Guo National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China School of Metallurgy and Materials University of BirminghamEdgbastonBirmingham B152TTUK

Initially defined high entropy alloys(HEAs)usually exhibit a single-phase solid-solution ***,two and/or more types of phases in HE As possibly induce the desired microstructure features,which contribute to improving the wear properties of HE ***,we prepare a series of(AlCoCrFeNi)_(100-x)Hf_(x)(x=0,2,4and 6;at%) HEAs and concern their phase compositions,micro structures and wear *** leads to the formation of(Ni,Co)_(2)Hf-type Laves phase and tailors the microstructure from a body-centered cubic(BCC) singlephase structure to a hypoeutectic *** increased hardness from~HV 512.3 to~HV 734.1 is due to solid-solution strengthening,grain refinement strengthening and precipitated phase *** a few oxides(Al_(2)O_(3)+Cr_(2)O_(3)) caused by the wear heating contribute to an 85.5% decrease in wear rate of the HEA system from6.71×10^(-5) to 0.97×10^(-5) m^(3)·N^(-1)·m^(-1).In addition,Hf addition changes the wear mechanism from abrasive wear,mild oxidative wear and adhesive wear to oxidative wear and adhesive wear.

关键词： High entropy alloy Laves phase Hardness Wear mechanism

Introduction of rare-earth element Sc in alloy design to modify wear features of dual-phase high-entropy alloy

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Rare Metals 2024年第2期43卷 817-828页

作者： Hao Ren Rui-run chen Xue-Feng Gao Tong Liu Gang Qin Yu-Lung Chiu Shi-Ping Wu Jing-Jie Guo Guo National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin150001China School of Metallurgy and Materials University of BirminghamBirminghamB152TTUK

Tailoring the alloy composition,which induces the hard secondary phase to increase hardness and strength to improve the wear features,is a feasible approach for developing wear-resistant metal ***,a group of(AlCoCrFeNi)_(100–x)Sc_(x)(x=0–2.0,at%)high-entropy alloys(HEAs)are designed and the phase compositions and wear behaviors are ***-doped HEA series contain the primary body-centered cubic(BCC)and eutectic phases,in which the eutectic phase is composed of the alternately grown BCC and Laves *** addition promotes the diffusion of Ni atoms from BCC phase to form the Sc-rich Laves phase at the grain *** hardness increases due to solid solution strengthening and second phase *** the second phase strengthening plays a more significant role relative to solid solution *** phase and the oxides caused by wear heating prevent the direct contact between friction pair and HEAs,thus inducing a decreased wear rate from 6.82×10^(−5) to 3.47×10^(−5)m^(3)·N^(−1)·m^(−1).Moreover,the wear mechanism changes from adhesive wear,abrasive wear and oxidative wear to abrasive wear and oxidative wear.

关键词： High entropy alloy(HEA) Laves phase Hardness Wear mechanism

Diversification of interfaces triggered hydrogen storage properties enhancement

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Rare Metals 2024年第5期43卷 2324-2330页

作者： Jia-Xin Zhang Xin Ding Rui-run chen Xiang-Feng Ma Wen-Chao Cao Yong Zhang Jing-Jie Guo National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

Dual effects of grain refinement and alloying are achieved and the mechanism of"diverse interfaces reinforcement"for hydrogen storage Mg alloys is first *** interface reinforced Mg-Y-Zn-Al alloy for hydrogen storage is *** work figures out that the adventurous Al-rich phase exhibits an ordered face-centered cubic(FCC)structure with composition of(31±2)at%Y-(28±1)at%Zn-(41±3)at%Al,i.e.,Y_(3)Zn_(3)Al_(4),and an incoherent interface between Y3Zn3Al4phase and Mg substrate is observed.

关键词： hydrogen alloying alloy

Intermittent melena and refractory anemia due to jejunal cavernous lymphangioma:A case report

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1208-1214页

作者： Kai-Rui Liu Sheng Zhang Wei-run chen You-Xing Huang Xu-Guang Li Department of Abdominal Surgery The Second Affiliated Hospital of Guangzhou University of Chinese MedicineGuangzhou 510000Guangdong ProvinceChina Department of General Surgery The Affiliated Brain Hospital of Guangzhou Medical UniversityGuangzhou 510000Guangdong ProvinceChina Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and The Ministry of Education of China Guangzhou Medical UniversityGuangzhou 510000Guangdong ProvinceChina

BACKGROUND Lymphangiomas in the gastrointestinal tract are extremely rare in *** a benign lesion,small intestine lymphangiomas often remain asymptomatic and pose challenges for definitive ***,lymphangiomas can give rise to complications such as abdominal pain,bleeding,volvulus,and ***,we report a case of jejunal cavernous lymphangioma that presented with intermittent melena and refractory anemia in a male *** SUMMARY A 66-year-old man presented with intermittent melena,fatigue and refractory anemia nine months *** and colonoscopy were performed many times and revealed no apparent *** management,including transfusion,hemostasis,gastric acid secretion inhibition and symptomatic treatment,was performed,but the lesions tended to recur shortly after ***,the patient underwent capsule endoscopy,which revealed a more than 10 cm lesion accompanied by active *** singleballoon enteroscopy and biopsy,a diagnosis of jejunal cavernous lymphangioma was confirmed,and the patient underwent surgical *** complications or recurrences were observed *** Jejunal cavernous lymphangioma should be considered a cause of obscure gastrointestinal *** endoscopy and single-balloon enteroscopy can facilitate *** resection is an effective management method.

关键词： Intermittent melena Refractory anemia Capsule endoscopy Single-balloon enteroscopy Jejunal cavernous lymphangioma Enterectomy Case report

Modification of BCC phase and the enhanced reversible hydrogen storage properties of Ti-V-Fe-Mn alloys with varied V/Fe ratios

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China Foundry 2024年第5期21卷 546-554页

作者： Xiang-feng Ma Xin Ding En-lai Liu Rui-run chen Xin-xiu Wang Yong Zhang and Jing-jie Guo National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266500ShandongChina AECC Harbin Dongan Engine Co.Ltd.Harbin 150001China

Ti-V-based alloys are proved of huge potential in storing hydrogen,but the incomplete reversible hydrogen storage capacity caused by overstability of V hydride has limited the large-scale *** this study,Ti_(32)V_(40+x)Fe_(23-x)Mn_(5)(x=0,4,8,12,at.%)alloys were designed,and the effects of V/Fe ratio on phase constitution and hydrogen storage properties were *** main phase of the alloys is body-centered cubic(BCC)phase,and the lattice constants of the BCC phase decrease with the decrease of V/Fe ***,C14 Laves phase exists in alloys with a Fe content of 19at.%to 23at.%.For hydrogenation,the C14 Laves phase can accelerate the hydrogen absorption rate,but the hydrogen absorption capacity is *** the decrease of V/Fe ratio,the hydride gradually *** to its large lattice constant and high hydrogen absorption phase content,the Ti_(32)V_(52)Fe_(11)Mn_(5)alloy shows the most enhanced hydrogen storage properties with hydrogenation and dehydrogenation capacities of 3.588wt.%at 298 K and 1.688wt.%at 343 K,*** hydrogen absorption capacity of this alloy can be reserved to 3.574wt.%after 20 cycles of hydrogen absorption and desorption.

关键词： hydrogen storage Ti-based alloy lattice constant BCC phase

Application of fecal immunochemical test in colorectal cancer screening:A community-based,cross-sectional study in averagerisk individuals in Hainan

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World Journal of Gastrointestinal Oncology 2024年第8期16卷 3445-3456页

作者： Fan Zeng Da-Ya Zhang Shi-Ju chen run-Xiang chen chen chen Shi-Mei Huang Da Li Xiao-Dong Zhang Jia-Jia chen Cui-Yi Mo Lei Gao Jun-Tao Zeng Jian-Xin Xiong Zhai chen Fei-Hu Bai Graduate School Hainan Medical UniversityHaikou 571199Hainan ProvinceChina Department of Gastroenterology Qionghai People’s HospitalQionghai 571400Hainan ProvinceChina Department of Gastroenterology Sanya Central HospitalSanya 572022Hainan ProvinceChina Department of Gastroenterology Hainan Second People’s HospitalWuzhishang 572299Hainan ProvinceChina Department of Gastroenterology Dongfang People’s HospitalDongfang 572699Hainan ProvinceChina Department of Gastroenterology The Second Affiliated Hospital of Hainan Medical UniversityHaikou 570216Hainan ProvinceChina The Gastroenterology Clinical Medical Center of Hainan Province Haikou 570216Hainan ProvinceChina

BACKGROUND The incidence of colorectal cancer(CRC)in China is steadily rising,with a high proportion of advanced-stage *** highlights the significance of early detection and prevention measures to enhance survival *** immunochemical testing(FIT)is a globally recommended CRC screening method;however,limited research has been conducted on its application in *** To assess the efficacy and adherence of FIT screening among average-risk individuals in Hainan,while also examining the risk factors associated with positive FIT *** This population-based cross-sectional study implemented FIT screening for CRC in 2000 asymptomatic participants aged 40-75 years from five cities and 21 community health centers in Hainan *** study was conducted from August 2022 to April 2023,employing a stratified sampling method to select *** with positive FIT results subsequently underwent *** predictive values for confirmed CRC and advanced adenoma were calculated,and the relationship between relevant variables and positive FIT results was analyzed usingχ2 tests and multivariate logistic *** A total of 1788 participants completed the FIT screening,with a median age of 57 years(interquartile range:40-75).Among them,503(28.1%)were males,and 1285(71.9%)were females,resulting in an 89.4%compliance rate for FIT *** overall positivity rate of FIT was 4.4%[79 out of 1788;95%confidence interval(CI):3%-5%].The specific positivity rates for Haikou,Sanya,Orient City,Qionghai City,and Wuzhishan City were 9.6%(45 of 468;95%CI:8%-11%),1.3%(6 of 445;95%CI:0.1%-3.1%),2.7%(8 of 293;95%CI:1.2%-4.3%),3.3%(9 of 276;95%CI:1.0%-6.3%),and 4.2%(11 of 406;95%CI:1.2%-7.3%),*** associations were found between age,dietary habits,and positive FIT *** of the 79 participants with positive FIT results,55 underwent colonoscopy,demonstrating an 82.2%compliance *** them,10 had a clean

关键词： Fecal immunochemical test Colorectal cancer Adenoma Screening Hainan Province

基于H_(∞)滤波器的LCL型并网逆变器有源阻尼方法

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电源学报 2024年第4期22卷 121-132页

作者：陈润曾君刘俊峰华南理工大学电力学院广州510640 华南理工大学自动化科学与工程学院广州510640 中国电源学会

LCL型滤波器具有优越的高频谐波抑制性能,但会造成谐振和稳定性问题。对于LCL型并网逆变器,传统的电容电流反馈型有源阻尼方法能有效抑制谐振尖峰,但是需要额外的电流传感器。为此,提出一种基于H_(∞)滤波器的新型有源阻尼控制策略。根... 详细信息

LCL型滤波器具有优越的高频谐波抑制性能,但会造成谐振和稳定性问题。对于LCL型并网逆变器,传统的电容电流反馈型有源阻尼方法能有效抑制谐振尖峰,但是需要额外的电流传感器。为此,提出一种基于H_(∞)滤波器的新型有源阻尼控制策略。根据LCL型滤波器状态空间模型及过程噪声模型完成H_(∞)滤波器的求解,可利用入网电流和公共耦合点电压信息估计滤波电容电流并完成反馈,增大系统阻尼,即使LCL型滤波器参数发生摄动也仍能保持估计值的精确度。仿真和实验结果表明,该方法对LCL滤波器参数变化和电网阻抗变化不敏感,验证了该方法的可行性和优势。

关键词： LCL型滤波器并网逆变器有源阻尼 H_∞滤波器