FRACTURE SURFACE MORPHOLOGY OF CARBON/EPOXY COMPOSITES

1986 ◽  
pp. 555-562
Author(s):  
A. Krsovi ◽  
M. Jirous ◽  
Z. Sucharda
2021 ◽  
Vol 39 (2A) ◽  
pp. 196-205
Author(s):  
Zainab M. Abdul Monem ◽  
Jawad K. Oleiwi ◽  
Qahtan A. Hamad

In the current Research , the heat cured   matrix material powder of PMMA was reinforced with peanut and walnut shells (natural powders) which are chemically treated with 5% (w/v) (NaOH) to improve the matrix bonding (PMMA) before being used as a reinforcing powder and adding to exactly similar averages particle sizes ≤ (53µm), with different weight fractions of (4, 8, and 12 wt.%). The ASTM D638 is used for composite specimens of the tensile test. The results indicated that the Elastic modulus values reached its maximum value at (8 wt.%.) when reinforced with peanut shells particles (1.053Gpa) , while ,the values of tensile strength, elongation percentage at break, decrease as the weight fraction of peanut and walnut shells powder increase and the lowest values is obtained by reinforcing with peanut shells particles to reach their minimum values at (12 wt.%.) where the lowest values of them are (29 MPa, 2.758% ) respectively. The fracture surface morphology of pure PMMA seemed to be homogenous morphology in (SEM) test, whereas the fracture surface morphology of PMMA composite reinforced by (peanut and walnut shells) powders and shows a roughness fracture surface morphology this refer to semi ductile to ductile materials.


2013 ◽  
Vol 469 ◽  
pp. 148-151
Author(s):  
Zhi Jian Li ◽  
Qing Jun Meng

The Green food-packaging membranes were prepared with N-methylmorpholine-N-oxide (NMMO) as the major solvent by using L-S phase inversion technique. Scanning electron microscopy (SEM) was adopted to characterize fracture surface morphology of membrane, and tensile machine was adopted to test the membrane strength performance. Research results show with the concentration of cellulose increases from 5% to 9%, structure of membrane becomes compact, aperture size becomes small and even, value of tensile strength increases 59.6%, and value of elongation increases 67.5%. With dissolving temperature increases from 100°C to 120°C, structure of membrane becomes loose, pore size becomes big and uneven, value of tensile strength decreases 19.2%, and value of elongation decreases 13.1%. The research can provide the theoretical reference for optimizing technology, adjusting the structure of membrane, and improving the performances of membrane.


2013 ◽  
Vol 3 (0) ◽  
Author(s):  
Alena Juríková ◽  
Jozef Miškuf ◽  
Kornel Csach ◽  
Elena Tabachnikova ◽  
Vladimír Bengus

2003 ◽  
Vol 800 ◽  
Author(s):  
Y. D. Lanzerotti ◽  
J. Sharma ◽  
R. W. Armstrong ◽  
R. L. McKenney ◽  
T. R. Krawietz

ABSTRACTThe characteristics of TNT (trinitrotoluene) crystals in the fracture surface of Composition B (a melt-cast mixture of TNT and RDX) have been studied using atomic force microscopy (AFM). The size of TNT crystals has been examined by analyzing the surface structure that is exhibited after mechanical failure of the Composition B. The failure occurs when the material is subjected to high acceleration in an ultracentrifuge and the shear or tensile strength is exceeded. AFM examination of the topography of the Composition B fracture surface reveals fracture across columnar grains of the TNT. The width of the columnar TNT grains ranges in size from ∼ 1 μm to ∼ 2 μm. Their height ranges in size from ∼ 50 nm to ∼ 300 nm. Flat TNT columns alternate with TNT columns containing river patterns that identify the direction of crack growth. Steps in the river patterns are a few nanometers in depth. The TNT constitutent fracture surface morphology is shown to occur on such fine scale, beginning from adjacent columnar crystals only 1–2 μm in width, and including river marking step heights of only a few nanometers, that AFM-type resolution is required.


2011 ◽  
Vol 264-265 ◽  
pp. 355-360 ◽  
Author(s):  
Saeid Norouzi ◽  
Hassan Farhangi

In the present study, the effect of cooling condition on hot tearing tendency and hot tearing fracture surface morphology were investigated. Results show that, the hot tear fracture surface characteristics are nearly similar under different cooling conditions. The hot tear surface exhibits two main features; the brittle region and the ductile region. The results also indicate that cooling condition has multifaceted effects on hot tearing phenomenon. Increasing cooling rate increases the thermal gradient, which raises the hot tearing tendency; concomitantly it decreases the grain size and dendrite arm spacing which increases the strength of the material. The occurrence of hot tearing phenomenon under different cooling conditions is discussed and evaluated based on the competition between these opposing factors during the solidification process.


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