Cui-Hong Li
,
Qi-Qiang Duan
,
Zhe-Feng Zhang
金属学报(英文版)
doi:10.1007/s40195-016-0371-8
A new parameter, i.e., tearing toughness, was employed to characterize the mechanical properties of some ductile metals (Cu, Cu-2 wt% Be, Cu-Al alloys, and some steels) by using three-leg trousers tearing tests. The experimental results demonstrate that their tearing toughness is not a physical constant and shows a close relationship with the materials’ types and microstructures. It can be inferred that the tearing toughness of different ductile metals has their respective variation range, expectantly, and may be represented by the comprehensive mechanical properties of strength and ductility for various ductile materials.
关键词:
Ductile
,
metals
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Strength
,
Ductility
,
Tearing
,
toughness
SI Zhongyao WANG Zhaoqing LIU Peng YU Dehua LIU Lei ** Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China*** Capital Iron and Steel Company
,
Beijing
,
100053
,
China+ To whom correspondence should be addressed
材料科学技术（英文）
Effects of microalloying Ti and B on the microstructures and low temperature toughness of manual metal arc (MMA) deposits were investi- gated.Weld metals containing 200-300 ppm Ti and 29-60 ppm B deposited by manual coated elec- trodes provided an optimum low temperature toughness.The addition of B in weld metals low- ered the γ→α transformation temperature which promoted the acicular ferrite (AF) transformation. Solid solutioned B suppressed grain boundary ferrite as well as side plate ferrite formation and benefited the acicular ferrite formation.Titanium protected B from oxidizing as well as nitriding and formed Ti-Mn silicate inclusions.Ultra-high volt- age electron microscope analyses showed that TiO structure in the Ti-Mn silicate inclusions was the favorable nucleation site for acicular ferrite forma- tion.
关键词:
toughness
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null
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null
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null
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null
Physical Review B
A perimeter-maximum-diameter method is proposed for measuring the fractal dimension of a fractured surface. The measured values of the fractal dimension by this method seem independent of the length of the yardstick. However, the fractal dimensions D(m) measured by the perimeter-area method decrease as the yardstick length increases. When the length of the yardstick is small enough, the value of D(m) measured by the latter method approaches the value measured by the present method.
关键词:
toughness
Physical Review E
This paper discusses the relation between fractal dimension and roughness index for fractal surfaces of solids. The applicability of the relation to fracture of Mode III+Mode I complex loading is shown. The applicability to other rough surfaces is discussed. [S1063-651X(99)09210-7].
关键词:
toughness
B.C.Samanta
,
T.Maity
材料科学技术（英文）
An investigation was carried out to modify the toughness of triethylene tetramine cured DGEBA (diglycidyl ether of bisphenol-A) resin using solid amine terminated poly (ethylene glycol) benzoate (ATPEGB) as modifier with and without red mud waste particles. The solid ATPEGB modifier synthesized from the acid catalyzed esterification reaction of poly (ethylene glycol) (PEG) and 4-amino benzoic acid was characterized by Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR (nuclear magnetic resonance) spectroscopies, viscosity measurements, and solubility parameter calculation. The unfilled and red mud waste filled modified epoxy networks were evaluated with impact, adhesive, tensile, flexural and thermal properties by differential scanning calorimetry (DSC), thermogravimetric (TG) and dynamic mechanical analysis (DMA). The effect of modifier concentration and red mud waste particles on toughening behavior was also investigated. The optimum properties were obtained at 12.5 phr (parts per hundred parts of resin) concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315℃. The morphology on fracture surfaces of cured epoxy was also analyzed by scanning electron microscopy (SEM).
关键词:
Epoxy
,
toughness
,
adhesive
,
morphology
Liang ZHEN Yuexian CUI Dezhuang YANG Department of Materials Science
,
Harbin Institute of Technology
,
Harbin
,
150006
,
ChinaShenglong DAI Guifu YU Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China
材料科学技术（英文）
The formation of precipitation free zone (PFZ) and its effect in a RSP AI-Li alloy has been studied. The results show that PFZ is easy to form when aged at 190℃,but there is no equilibrium phase on grain boundaries.The growth of PFZ in the alloy is different from that in conventional AI-Li alloys, The effect of PFZ is of great importance because of its large volume fraction in the alloy.It offsets the beneficial effect of RSP,and is thought to be an important factor that leads to the poor toughness and low ductility of RSP AI-Li alloy sheet.
关键词:
precipitation free zone
,
null
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null
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null
LIU Qingquan ZHANG Xiumu TENG Huayuan WANG Yikang Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
The investigation on lath martensitic transfor- mation has been carried out for 24SiMnNi2CrMoA steel using transmission electron microscopy (TEM) and X-ray diffraction.The austenite and martensite in the alloy adopt the intermediate orientation relationship between Kurdjumov-Sachs and Nishiyama.The adjacent laths in a packet are small-angle related or twin-related.The retained austenites which accommodate shape deformation of martensites appear commonly between adjacent laths.High Si content increases the volume fraction of retained austenites and its stability.The excellent combination of high strength and toughness of this steel is attributed to its fine martensite laths mingled with more than 5% continuous retained austenite films.
关键词:
martensitic transformation
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null
,
null
,
null
ZHENG Yesha WANG Zhongguang AI Suhua State Key Laboratory of Fatigue and Fracture for Materials
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China postdoctor
,
Shanghai Institute of Ceramics
,
Academia Sinica
,
Shanghai 200050
,
China
金属学报(英文版)
It is obtained in this paper that the fatigue threshold value of mode H was 1.9 times of that of mode Ⅰ in dual-phase steel(DPS),and the normal stress intensity factor range oJ mode Ⅱ branch crack tip was 2.2 times of that of mode Ⅰ.Above results illustrate that the resistance of mode Ⅱ crack growth was higher than that of mode Ⅰ,the former resulting from roughness-induced shear resistance,the latter,crack closure. The mode Ⅱ component can play two important roles in near-threshold fatigue crack growth:(1)increasing crack tip plasticity which accelerates the crack growth and(2)intro- ducing crack surface contact and rubbing to reduce the crack propagation rate.By means of crack closure,the quantity of shear resistance was easily solved in this paper.The friction shear stress strength factor range of mode Ⅱ,K_,is still much higher than the closure stress strength factor range of mode Ⅰ,K_(Ⅰ,cl).This illustrated that the roughness enlarged the second role and played a role of shielding crack tip from mode Ⅱ crack.
关键词:
mixed-mode(Ⅰ/Ⅱ)fatigue crack growth threshold
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null
,
null
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null
,
null
CHENG Tianyi Beijing Institute of Technology
,
Beijing
,
ChinaCANTORB University of Oxford
,
UKMcLEANM FLOWERHM Imperial College
,
UK CHENG Tianyi
,
associate professor
,
Faculty of Metallography
,
Beijing Institute of Technology
,
Beijing 100081
,
China
金属学报(英文版)
In rapidly solidified Ni-34.6 at-% Al alloy,when the cooling the rate during solidification reached the order of 10~6 K/s,the size of the microstructures,such as the grains and substructure of the martensite,decreased dramatically.The various kinds of interfaces with high density and homogeneous distribution resisted effectively the propagation of the cracks and resulted in localized plastic deformation ahead of the tips of microcracks.The ductility and toughness at room temperature of the Ni-rich NiAl may be improved considerably.
关键词:
NiAl
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null
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null
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null
