Mechanical Behavior and Fatigue in Polymeric Composites at Low Temperatures

The traditional method preparing Si3N4/Si2N2O composite ceramic is to sinter α-Si3N4 powder with additives at relatively high temperatures. But the intergranular phase transformed from the sintering additives can degrade the high-temperature mechanical behavior. Amorphous nanoSi3N4 is used to fabricate Si3N4/Si2N2O composite ceramic by its oxidation and nitridation without sintering additives at low temperatures. Thus, it is essential to study the oxidation behavior and mechanism of amorphous nanoSi3N4. Amorphous nanoSi3N4 powders were oxidized in different atmospheres, at varying temperatures and for various different length of time. The oxidation process and products was analyzed by means of XRD, TGA and FTIR. The results showed that amorphous nanoSi3N4 could be oxidized into SiO2 from 600°C to 1300°C. Below 1300°C, the oxidation became serious as the temperature increased. Besides, the longer the oxidation time and the lager the ratio of O2/N2 partial pressure was, the deeper the oxidation level was. When the temperature was above 1300°C, amorphous nanoSi3N4 was completely oxidized into SiO2.

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Dynamic mechanical behavior of polystyrene, poly-p-chlorostyrene, and poly-p-bromostyrene at low temperatures

Journal of Polymer Science ◽

10.1002/pol.1959.1204113850 ◽

1959 ◽

Vol 41 (138) ◽

pp. 528-531 ◽

Cited By ~ 46

Author(s):

K. H. Illers ◽

E. Jenckel

Keyword(s):

Mechanical Behavior ◽

Low Temperatures ◽

Dynamic Mechanical ◽

Dynamic Mechanical Behavior

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Considerations in Low-Temperature Mechanical Behavior of Polymer Composite Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.760.323 ◽

2015 ◽

Vol 760 ◽

pp. 323-328

Author(s):

Stefan Cotae ◽

Constantin Popescu ◽

Horatiu Iancau

Keyword(s):

Tensile Strength ◽

Mechanical Behavior ◽

Fiber Orientation ◽

Low Temperatures ◽

Composite Structures ◽

Room Temperature ◽

Experimental Program ◽

Independent Variables ◽

Factorial Method ◽

Degree Of Reinforcement

In this paper it has been sought to highlight the mechanical behavior of composite structures at low temperatures compared to mechanical behavior at room temperature. For researches an experimental program has been conceived and built using factorial method. In this method, as dependent variable was taken the tensile strength (σr), while as independent variables were taken: the fiber orientation angles (θ), the degree of reinforcement (Mf) of the composite structure and the temperature (t) at which the tests were carried out (+25°C,-25°C and-50°C respectively). It has been used a complex experimental installation, specific to tests at low temperatures.

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Dislocation Core Structures and Mechanical Behavior of DO22 Type Alloys

MRS Proceedings ◽

10.1557/proc-213-229 ◽

1990 ◽

Vol 213 ◽

Author(s):

M. Khantha ◽

V. Vitek ◽

D.P. Pope

Keyword(s):

Mechanical Behavior ◽

Low Temperatures ◽

Dislocation Core ◽

Intermetallic Alloy ◽

Tetragonal Distortion ◽

The Core ◽

External Stresses

ABSTRACTWe investigate the structures of dislocation cores in a model DO22 type intermetallic alloy in the absence of external stresses. The tetragonal distortion produces sessile configurations of superpartial dislocations even when the energies of planar faults are reasonably low. The influence of the core configurations on the mechanical behavior at low temperatures is discussed.

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