Photoelastic characterization of shear‐bands in mechanically stretched polymeric fibers

2021 ◽  
Author(s):  
Taha Z. N. Sokkar ◽  
Mohammed A. El‐Bakary ◽  
Amira A. S. Azam ◽  
Ahmed A. Hamza
Keyword(s):  
Shear Bands ◽  
Polymeric Fibers

Mechanical characterization of craters induced by impacting foreign objects on Inconel718

2017 ◽  
Vol 27 (6) ◽  
pp. 937-949 ◽  
Author(s):  
Hamed K Farahani ◽  
Mostafa Ketabchi ◽  
Shahab Zangeneh
Keyword(s):  
Shear Bands ◽  
Compressor Blades ◽  
Ball Impact ◽  
Foreign Object Damage ◽  
Nickel Based Superalloy ◽  
Foreign Objects ◽  
High Pressure Compressor ◽  
Stress Concentration Factors ◽  
Steel Balls

In this study, foreign object damage on aircraft high pressure compressor blades made of Inconel718 nickel-based superalloy was experimentally simulated at the working temperatures of the blades. Steel balls (as a foreign objects) with velocities of 292, 208, 133 m/s were impacted on the surface of Inconel718 flat specimens at various temperatures (400, 475, 550, and 625℃). In order to characterize induced craters, impact sites were studied by scanning electron microscopy to identify mechanical features such as microcracks and notches. Then, the specimens were 3D scanned to measure the depth of each crater. It was found that variation of stress concentration factors and induced damages (including microcracks and notches, loss of material, and shear bands) could occur as a result of steel ball impact with velocities of 292 and 133 m/s at temperatures of 625 and 400℃, respectively.

Shear Band Feature in Two Bulk Metallic Glasses with Different Inherent Plasticity

2013 ◽  
Vol 703 ◽  
pp. 20-23
Author(s):  
Jian Sheng Gu ◽  
Hui Feng Bo ◽  
Hong Li ◽  
Zhan Xin Zhang
Keyword(s):  
Plastic Deformation ◽  
Shear Band ◽  
Temperature Rise ◽  
Metallic Glasses ◽  
Shear Banding ◽  
Shear Bands ◽  
Significant Difference ◽  
Coating Method ◽  
Deformation Ability

Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 BMGs was studied by using Rockwell indention method. The significant difference in plastic deformation ability can be ascribed to different shear banding features. Meanwhile, by using the fusible coating method, thermal effect on shear bands was investigated. We did not see apparently temperature rise in shear bands of these two BMGs through Rockwell indentation.

Recrystallization Kinetics and Texture Evolution during Annealing of Cold Rolled Fe-Mn-C Alloy

2012 ◽  
Vol 715-716 ◽  
pp. 568-573 ◽  
Author(s):  
Ya Ping Lü ◽  
Dmitri A. Molodov ◽  
Günter Gottstein
Keyword(s):  
Texture Evolution ◽  
Shear Bands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recrystallization Kinetics ◽  
Nucleation Sites ◽  
Preferential Nucleation ◽  
Cold Rolled ◽  
Mechanical Twins

The recrystallization behavior of 50% cold rolled Fe-22%Mn-0.376%C alloy during annealing at 560°C, 630°C and 700°C was investigated. Microhardness tests were applied for characterization of the recrystallization kinetics, X-ray diffraction and EBSD measurements were utilized to characterize the crystallographic texture and the grain microstructure. The obtained experimental data were evaluated in terms of the JMAK model. The obtained values of the Avrami exponent varied in the range between 0.70 and 1.37. The inhomogeneous grain microstructure after recrystallization is interpreted in terms of non-randomly distributed nuclei. Shear bands, lamellar lines intersecting with mechanical twins and grain boundaries with localized high misorientation gradients were identified to be preferential nucleation sites. No pronounced texture was observed after annealing at 630°C.

scholarly journals Mechanical and Microstructural Characterization of an AZ91–Activated Carbon Syntactic Foam

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 3 ◽  
Author(s):  
Nima Movahedi ◽  
Mehdi Taherishargh ◽  
Irina Belova ◽  
Graeme Murch ◽  
Thomas Fiedler
Keyword(s):  
Activated Carbon ◽  
Shear Bands ◽  
Syntactic Foam ◽  
Microstructural Characterization ◽  
Az91 Alloy ◽  
Syntactic Foams ◽  
Static Compression ◽  
Carbon Particles ◽  
Activated Carbon Particles

In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a magnesium syntactic foam. This novel lightweight foam has a very low density, in the range of 1.12–1.18 gcm−3. The results show that no chemical reaction occurred between the AZ91 matrix and the activated carbon particles. The mechanical properties of the foam were evaluated under quasi-static compression loading conditions, and showed a consistent trend for the energy absorption of the fabricated AZ91–AC syntactic foams. The deformation mechanism of samples was a brittle fracture mode with the formation of shear bands during the fracture of all samples.

Characterization of Shear Bands in Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 BMGs

2013 ◽  
Vol 703 ◽  
pp. 24-28
Author(s):  
Jian Sheng Gu ◽  
Hui Feng Bo ◽  
Hong Li ◽  
Zhan Xin Zhang
Keyword(s):  
Plastic Deformation ◽  
Shear Band ◽  
Shear Banding ◽  
Shear Bands ◽  
Band Pattern ◽  
Significant Difference ◽  
Deformation Ability

Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10and Zr65Cu15Ni10Al10BMGs was studied by using Rockwell indention method. Well-developed shear band pattern can be found for both BMGs after indentation. The significant difference in plastic deformation ability can be ascribed to different shear banding features.

Synthesis and Characterization of Nanosized NiAl Particles

1998 ◽  
Vol 520 ◽  
Author(s):  
T. Chen ◽  
J.M. Hampikian
Keyword(s):  
Solid State ◽  
Mechanical Alloying ◽  
Long Range ◽  
Solid State Reaction ◽  
Shear Bands ◽  
Range Order ◽  
Long Range Order ◽  
Mechanically Alloyed ◽  
Edge Dislocations

ABSTRACTNanophase NiAl powders were synthesized by solid state reaction via ball milling of elemental Ni and Al powders under an argon atmosphere for 0-8 h, 16 h, 24 h, and 48 h. Structural characterization of the nanophase NiAI was performed by x-ray diffraction and transmission electron microscopy. The oxidation behavior of the powders was studied by thermogravimetric analysis. It was found that the Ni + Al = NiAl solid state reaction took place between 4 and 5 hours of mechanical alloying. After 5 h or more of mechanical alloying, the phase of the ball milled particles was the B2 structure, with average grain sizes which decreased with increasing mechanical alloying times. The relationship between the long-range-order parameters and mechanical alloying time was studied. After 5 h, 6 h, 8 h, 16 h, 24 h, and 48 h mechanical alloying, the long-range-order parameter was determined to be approximately 0.82, 0.75, 0.75, 0.75, 0.71, and 0.63, respectively. Iron contamination was observed, resulting from wear of the steel vial and balls. In the mechanically alloyed NiAl nanoparticles, edge dislocations, shear bands, subgrains, distorted regions, and a large number of grain boundaries were observed.

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