胡小波
,
阳志安
,
王中光
材料研究学报
Al-3.36wt-%Mg 合金在中温下的循环蠕变实验结果表明,在一定的温度和应力范围内,循环蠕变的第一和第二阶段都有应变突发发生,且这类应变突发具有明显的周期性,是动态应变时效的结果。根据McCormick 提出的位错与溶质原子交互作用模型,讨论了应变突发时的位错运动机制,从而说明了应变突发周期随应变速率单调变化的规律。
关键词:
铝镁合金
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cyclic creep
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strain burst
,
dynamic strain aging
YI Jianzhang Shenyang Institute of Aeronautical Engineering
,
Shenyang
,
ChinaYANG Zhi'an ZHU Shijie WANG Zhongguang Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China lecturer
,
Department of Safety Engineering
,
Shenyang Institute of Aeronautical Engineering
,
Shenyang 110031
,
China
金属学报(英文版)
Vertical section method has been used to measure the fractal dimension of cyclic creep frac- ture surfaces of rotor steel 34CrMoA at 550℃.The relationship between fractal dimension and cyclic creep properties has been analyzed.The fractal dimension is dependent upon the power product of minimum creep rate and rupture time,and satisfies the linear function with rupture strain.
关键词:
cyclic creep
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null
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null
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null
Author M.F. Geng1)
,
T. Wang1) and X.A. Zhang2) 1) Department of Special Metal Materials and Products
,
Luoyang Ship Material Research Institute
,
Luoyang 471039
,
China2) Mechanical Properties Laboratory
,
Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China Manuscript received18 October 1998
金属学报(英文版)
The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens under a wide range of load levels and various periods of hold time, and the fracture surfaces were examined on a scanning electron microscope. The results show that, for both static and cyclic creep, Stage-I of crack growth is related with initial test stress, during which the crack extension is about 0.5mm, and that the final effect of cyclic loading on rupture life depends on the counteraction of its two reversed effects on crack growth rate before and after the point n=0.2.
关键词:
cyclic creep
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null
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null
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null
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null
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null
ZHU Shijie YANG Zhian WANG Zhongguang State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
Shenyang
,
110015
,
ChinaTo whom correspondence should be addressed
材料科学技术（英文）
Cyclic creep tests of Al-Mg alloy have been conducted at a wide range of stress and temperature.When Mg content is beyond 0.45%, the strain bursts can be observed in the cyclic creep curves.There exists a critical stress for the occur- rence of the strain burst,which increases with an in- crease of Mg content and is almost 60% of the ul- timate tensile stress.The occurrence of strain burst is proposed to be controlled by the easiness of the cross-slip of dislocations.For Al-Mg alloy,the dynamic strain aging plays an important role in the strain bursts.
关键词:
cyclic creep
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null
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null
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null
王翔
,
孔庆平
,
佟世华
,
江先美
,
任卫平
金属学报
本文研究了热电站用12Cr1MoV钢在550℃的蠕变-疲劳复合性能(即循环蠕变性能).实验结果表明,在较高应力幅下,循环蠕变寿命大于纯蠕变寿命,试样断裂以穿晶型为主.在较低应力幅下,循环蠕变寿命小于纯蠕变寿命,试样发生晶间型断裂.根据对断裂试样内部位错组态和晶界状态的透射电镜观察,认为在不同应力幅下分别发生循环强化和循环弱化的原因是:在较高应力下,晶内损伤在循环蠕变的卸载过程中得以部分回复;而在较低应力下,叠加交变应力加速了晶间空洞的形成和连接.
关键词:
12Cr1MoV钢
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cyclic creep
,
rupture
ZHU Shijie YANG Zhian WANG Zhongguang ** State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China+ To whom correspondence should be addressed
材料科学技术（英文）
Static creep and cyclic creep tests were carried out on a Cr-Mo rotor steel from 0.5 to 0.6 T_m. Cyclic creep retardation occurred under the test conditions.With an increase of stress frequency, cyclic creep strain rate decreases and rupture time increases.The cyclic creep strain rate for the stress wave of a square shape is higher than that of a tri- angle shape.The apparent stress exponent of cyclic creep and the apparent activation energy of cyclic creep are both higher than those of static creep.The minimum strain rate is inversely proportional to rupture time for both static and cyclic creeps at dif- ferent stresses,temperatures,frequencies and wave shapes.The cyclic creep retardation mechanism was explored by the observation and analysis of the dis- location structure and fracture surface.
关键词:
fracture
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null
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null
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null
