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Recrystallization of Single Crystal Nickel-Based Superalloy

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Journal of Iron and Steel Research International 2009年第6期16卷 75-79页

作者： ZHANG Bing TAO Chun-hu LU Xin LIU Chang-kui HU Chun-yan BAI Ming-yuan failure analysis center of avic Beijing Institute of Aeronautical Materials Beijing 100095 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

A series of experiments of investigating the recrystallization of single crystal DD3 superalloy were carried out. The threshold temperature for recrystallization and the effect of annealing temperature on recrystallization were studied. The results show that the threshold temperature for recrystallization of the shot-peened DD3 samples is between 1 000 ℃ and 1 050 ℃ under the condition of annealing for 2 h, and the recrystallization depth increases with the rise of the annealing temperature. Below 1 150 ℃, the recrystallization depth increases slowly with the temperature climbing, while above 1 150 ℃, the recrystallization depth increases quickly with the rise of the temperature. The solution of the γ＇ phase is a critical factor of the recrystallization behavior of DD3 superalloy. In addition, the kinetics and microstructural evolution of recrystallization at 1 200 ℃ were also studied. It is found that the recrystallization progresses rapidly at 1 200 ℃ through the growth of fully developed recrystallized grains, and the recrystallization process on the shot-peened surface is similar to that of wrought materials, including nucleation of recrystallization, growth of new grains into the matrix, and growth of new grains by swallowing up each other.

关键词： single crystal superalloy recrystallization shot peening

failure analysis of crevice corrosion on 304 stainless steel tube heat exchanger

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Journal of Iron and Steel Research International 2023年第8期30卷 1490-1498页

作者： Chen Dong Shen Qu Chang-ming Fu Zhe-feng Zhang failure analysis center for Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina

The cause of the premature failure of 304 stainless steel tube heat exchanger was *** unique skeleton structure inside the leakage point reveals that this is a new damage mechanism caused by a δ+γ two-phase structure and crevice *** three-dimensional structure of the leakage point was demonstrated using X-ray diffraction *** results of scanning electron microscope examination show the microstructure of the weld to be columnar and *** is found by electron probe microscope analysis and transmission electron microscopy that columnar dendrites consisted of γ-dendrite and an amount of δ-ferrite phases at the dendrite *** corrosion test results confirmed that the corrosion medium was the chloride *** corrosion of chloride ions occurred at weld defects on the inner wall thus forming a concentration *** of columnar dendrites were then corroded by chloride ions and δ-ferrite phases on the grain boundaries were retained,which formed the particular skeleton corrosion *** a result,it led to leakage when the corrosion of weld occurred from the inner wall to the outer wall.

关键词： Crevice corrosion Weld defect Chloride ions δ-ferrite Skeleton structure 304 stainless steel

Effect of surface recrystallization on the creep rupture property of a single-crystal superalloy

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Rare Metals 2010年第4期29卷 413-416页

作者： ZHANG Bing LIU Changkui LU Xin TAO Chunhu JIANG Tao A VIC failure analysis center Beijing Institute of Aeronautical Materials Beijing 100095 China School of Materials Seienee andEngineering University of Science and Technology Beijing Beijing 100083 China

The effect of surface recrystallization by heating after shot-peening on the creep rapture property and fracture behavior of a single-crystal superalloy was investigated. The results show that the creep rupture property of the single-crystal superalloy was greatly influenced by surface recrystallization. A recrystallized surface layer with a depth of 101 ~m resulted in a decrease in creep rupture life by nearly 50%, and an almost linear reduction of creep rupture life was observed with the increase of recrystallization depth. A lower strength of the recrystal- lized layer, inhomogeneous deformation between the recrystallized layer and the matrix, and stress concentration caused by notch effect resuited in the decrease in creep rupture life of the single-crystal superalloy.

关键词： single crystal superalloy recrystallization shot peening creep rupture

analysis of crack opening stresses for center- and edge-crack tension specimens

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Chinese Journal of Aeronautics 2014年第2期27卷 291-298页

作者： Tong Di-Hua Wu Xue-Ren avic Beijing Institute of Aeronautical Materials

Accurate determination of crack opening stress is of central importance to fatigue crack growth analysis and life prediction based on the crack-closure model. This paper studies the crack opening behavior for center- and edge-crack tension specimens. It is found that the crack opening stress is affected by the crack tip element. By taking the crack tip element into account, a modified crack opening stress equation is given for the center-crack tension specimen. Crack surface displace- ment equations for an edge crack in a semi-infinite plate under remote uniform tension and partially distributed pressure are derived by using the weight function method. Based on these displacements, a crack opening stress equation for an edge crack in a semi-infinite plate under uniform tension has been developed. The study shows that the crack opening stress is geometry-dependent, and the weight function method provides an effective and reliable tool to deal with such geometry depen- dence.

关键词： center- and edge-crack Crack closure Crack opening stresses Crack surface displacements Weight function method

Cystatin C is a biomarker for predicting acute kidney injury in patients with acute-on-chronic liver failure

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World Journal of Gastroenterology 2013年第48期19卷 9432-9438页

作者： Zhi-Hong Wan Jian-Jun Wang Shao-Li You Hong-Ling Liu Bing Zhu Hong Zang Chen Li Jing Chen Shao-Jie Xin Liver failure Treatment and Research center Beijing 302 Hospital

AIM:To investigate serum cystatin C level as an early biomarker for predicting acute kidney injury(AKI)in patients with acute-on-chronic liver failure(ACLF).METHODS:Fifty-six consecutive patients with hepatitis B virus-related ACLF who had normal serum creatinine(Cr)level(failure Treatment and Research center of Beijing 302 Hospital between August 2011 and October *** patients with chronic hepatitis B(CHB)and 30 healthy controls in the same study period were also *** of serum cystatin C(CysC)was performed by a particle-enhanced immunonephelometry assay using the BN Prospec nephelometer *** ACLF patients were followed during their hospitalization ***:In the ACLF group,serum level of CysC was 1.1±0.4 mg/L,which was significantly higher(Panalysis indicated that CysC level was an independent risk factor for AKI development(odds ratio=1.8;95%CI:1.4-2.3,P=0.021).The cutoff value of serum CysC for prediction of AKI in ACLF patients was 1.21 mg/*** baseline CysC-based estimated glomerular filtration rate(eGFR CysC)was significantly lower than the creatinine-based eGFR(eGFR CG and eGFR MDRD)in ACLF patients with AKI,suggesting that baseline eGFR CysC represented early renal function in ACLF patients while the Cr levels were still within the normal ***:Serum CysC provides early prediction of renal dysfunction in ACLF patients with a normal serum Cr level.

关键词： Acute-on-chronic liver failure Cystatin C Creatinine Acute kidney injury Prediction

Clinical characteristics and corticosteroid therapy in patients with autoimmune-hepatitis-induced liver failure

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World Journal of Gastroenterology 2014年第23期20卷 7473-7479页

作者： Bing Zhu Shao-Li You Zhi-Hong Wan Hong-Ling Liu Yi-Hui Rong Hong Zang Shao-Jie Xin Liver failure Treatment and Research center 302~(nd) Military Hospital

AIM: To investigate the clinical features, response to corticosteroids, and prognosis of autoimmune hepatitis (AIH)-induced liver failure in China.

关键词： Autoimmune hepatitis Liver failure Autoantibody Prognosis Corticosteroid therapy

Large aftershocks triggering by Coulomb failure stress following the 2001 MS=8.1 great Kunlun earthquake

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Acta Seismologica Sinica(English Edition) 2004年第1期17卷 31-37页

作者： HAO Ping(郝平) FU Zheng-xiang(傅征祥) TIAN Qin-jian(田勤俭) LIU Jie(刘杰) LIU Gui-ping(刘桂萍) center for analysis and Predication China Seismological Bureau Beijing 100036 China Center for Analysis and Predication China Seismological Bureau Beijing 100036 China Center for Analysis and Predication China Seismological Bureau Beijing 100036 China Center for Analysis and Predication China Seismological Bureau Beijing 100036 China Department of Earthquake Monitoring and Predication China Seismological Bureau Beijing 100036 China

The great Kunlun earthquake occurred on Nov. 14, 2001 in Qinghai Province, China. Five large aftershocks with magnitude larger than 5.0 occurred near the Kunlun fault after main shock. Calculations of the change in Coulomb failure stress reveal that 4 of 5 large aftershocks occurred in areas with Dsf >0 (10-2~10-1 MPa) and one aftershock occurred in an area with Dsf =-0.56 MPa. It is concluded that the permanent fault displacement due to the main shock is the main cause of activity of large aftershocks, but not the whole cause.

关键词： Kunlun great earthquake aftershocks triggering Coulomb failure stress

Evaluation of vibration stress of TA11 titanium alloy blade by quantitative fractography

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Rare Metals 2014年第3期33卷 263-269页

作者： Xin-Ling Liu Yuan-Ming Xu Chun-Hu Tao Beijing Institute of Aeronautical Materials Aviation Industries of China Key Laboratory of Aeronautical Materials Testing and Evaluation ChinaTao failure analysis center of Aviation Industries of China School of Aeronautical Science and Engineering Beijing University of Aeronautics and Astronautics Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation

Vibration fatigue is the main failure mode of compressor blade. Evaluating the vibration stress of blade that leads to cracking is very useful for analysis of vibration fatigue. In this paper, fatigue stress estimation methods by quantitative fractography were studied through experimental blade and in-service first-stage compressor blade in order to evaluate the initiation vibration stress of in-service blade. The analysis process of initiation vibration stress was established. The evaluating result of vibration stress of in-service blade subjected to centrifugal force and bending vibration stress agrees with aero engine test result. It is shown that the evaluation method can not only evaluate the equivalent fatigue stresses of different crack depths but also yield the initiation equivalent fatigue stress.

关键词： Compressor blade Bending vibration Stress evaluate Quantitative fractography

Clinical characteristics and 28-d outcomes of bacterial infections in patients with hepatitis B virus-related acute-on-chronic liver failure

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World Journal of Clinical Cases 2020年第6期8卷 1042-1055页

作者： Chen Li Hai-Bin Su Xiao-Yan Liu Jin-Hua Hu Liver failure Treatment and Research center The Fifth Medical Center of Chinese PLA General HospitalBeijing 100039China

BACKGROUND Acute-on-chronic liver failure (ACLF),which includes hepatic and multiple extrahepatic organ failure,is a severe emergency condition that has high *** can rapidly progress and requires an urgent assessment of condition and referral for liver *** infections (BIs) trigger ACLF and play pivotal roles in the deterioration of clinical *** To investigate the clinical characteristics and 28-d outcomes of first Bis either at admission or during hospitalization in patients with hepatitis B virus (HBV)-ACLF as defined by the Chinese Group on the Study of Severe Hepatitis B(COSSH).METHODS A total of 159 patients with HBV-ACLF and 40 patients with acute decompensation of HBV-related chronic liver disease combined with first BIs were selected for a retrospective analysis between October 2014 and March 2016 The characteristics of BIs,the 28-d transplant-free survival rates,and the independent predictors of the 28-d outcomes were *** A total of 194 episodes of BIs occurred in 159 patients with *** the episodes,13.4 To were community-acquired,46.4 To were healthcare-associated,and 40.2% belonged to nosocomial *** (40.7%),spontaneous bacterial peritonitis (SBP)(34.5%),and bloodstream infection (BSI)(13.4%) were the most *** the ACLF grade increased,the incidence of SBP showed a downward trend (P=0.021).Sixty-one strains of bacteria,including 83.6% Gramnegative bacteria and 29.5% multidrug-resistant organisms,were cultivated from 50 patients with *** coli (44.3%) and Klebsiella pneumoniae (23.0%)were the most common *** the ACLF grade increased,the 28-d transplant-free survival rates showed a downward trend (ACLF-1,55.7%;ACLF-2,29.3%;ACLF-3,5.4%;P <0.001).The independent predictors of the 28-doutcomes of patients with HBV-ACLF were COSSH-ACLF score (hazard ratio[HR]=1.371),acute kidney injury (HR=2.187),BSI (HR=2.339),prothrombin activity (HR=0.967),and invasive cathete

关键词： Hepatitis B virus Acute-on-chronic liver failure Bacterial infections Outcomes Chronic liver disease Spontaneous bacterial peritonitis