材料期刊网

DAMAGE MECHANISMS OF INCONEL 738LC UNDER CREEP-FATIGUE LOADING CONDITIONS

M. Yamamoto and T. Ogata (Central Research Institute of Electric Power Industry , 2-11-1 , Iwado Kita , Komae-shi , Tokyo 201-8511 , Japan)

金属学报(英文版)

In order to investigate creep-fatigue life characteristics of Inconel 738LC, fatigue and creep-fatigue tests were carried out at 850℃. Significant life reduction to 30% to 50% of normal fatigue life, occurred when a strain hold period was introduced at the minimum compressive strain. Test results showed that the degree of life reduction did not depend on the length of hold time. To clarify the creep-fatigue damage mechanisms under creep-fatigue loading, in-situ SEM observations were carried out during the tests. In the tensile strain hold test, multi-site grain boundary cracking was observed from the beginning of the test. On the other hand, only a single main crack was observed in the compressive strain hold test. The crack propagated in an intergranular manner and it was different from the features observed under cyclic fatigue conditions. Through detailed observation, it was found that grain boundary sliding damage occured at most surface grain boundaries.

关键词: superalloy , null , null

Luoyang Institute of Refractories Research Ministry of Metallurgical Industry

ZHONG Xiangchong Luoyang Institute of Refractories Research , Luoyang , China.

材料科学技术（英文）

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EFFECT OF HOMOGENIZATION TREATMENT UNDER AN ELECTRIC FIELD ON T_1 DISTRIBUTION AND MECHANICAL PROPERTIES OF 2091 Al-Li ALLOY

LIU Wei , CUI Jianzhong(Northeastern University , Shenyang , ChinaManuscript received 10 November 1994)

金属学报(英文版)

Homogenization treatment under an electric field increases the distributive homogeneity of the T1 precipitation and improves the yield strength of 2091 Al-Li alloy.

关键词: :homogenization treatment , null , null , null

COMPUTERIZED SIMULATION AND EXPERIMENTAL RESEARCH ON SOFT-SWITCHING ARC WELDING INVERTER POWER SOURCE

S. J. Chen , S. Y. Yin , L. Feng and L. Y. Li( 1) School of Materials Science and Engineering , Beijing Polytechnic University , Beijing 100022 , China 2)National Key Laboratory of Advanced Welding Production Technology , HIT , Harbin 150001 , China)

金属学报(英文版)

Based on the existing component models in the Pspice software package, a combined model for Insulat- ed the Bipolar Transistor (IGBT) is established, in which a non - linear is introduced to represent the parasitic capacitance. Using this model, computerized simulation is conducted for the FB - ZVZCS - PWM soft - ewitching converter,the switching and energy-transferring characteristics of the components are analyzed.The simulation results are testified by experiments.It is proved that by abopting appropriate models,computerized simulation becomes an effective tool for investigation of arc welding inverter power source.

关键词: arc welding inverter , null , null

Influence of electric parameters on MAO of AZ91D magnesium alloy using alternative square-wave power source

Transactions of Nonferrous Metals Society of China

Micro-arc oxidation (MAO) process was carried out on AZ91D alloy in alkaline borate solution using an alternative square-wave power source with different parameters. The effects of voltage, frequency and duty cycle on the coatings were investigated by orthogonal experiment. It is found that the thickness of coatings increases with the increase of voltage and duty cycle, but decreases with the increase of frequency. The structure and morphology of the coatings also depend on voltage, frequency and duty cycle. The coatings become more porous and crack with increasing voltage and duty cycle. The coating is thin and transparent when the voltage is lower than 120 V. The corrosion resistances of different coatings were evaluated by polarization curves and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl (mass fraction) solution. When the optimized values of voltage, frequency and duty cycle are 140 V, 2 000 Hz and 0.4, respectively, the anodic coating shows the best corrosion resistance.

关键词: AZ91D magnesium alloy;micro-arc oxidation (MAO);alternative;square-wave;duty cycle;applied voltage;frequency;plasma electrolytic oxidation;mg-al alloys;corrosion behavior;anodic;films;coatings;additives;performance;resistance;phase

Study on Competitive Power of Rare Earth Industry in China

稀土学报(英文版)

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Study on Competitive Power of Rare Earth Industry in China

稀土学报(英文版)

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Study on Competitive Power of Rare Earth Industry in China

稀土学报(英文版)

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Study on Competitive Power of Rare Earth Industry in China

稀土学报(英文版)

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Study on Competitive Power of Rare Earth Industry in China

稀土学报(英文版)

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