scholarly journals Observation of tungsten particle deformation inside a shock compressed polymer

2020 ◽  
Author(s):  
David Bober ◽  
Moono Rhee ◽  
Nathan Barton ◽  
Mukul Kumar
Keyword(s):  
Tungsten Particle ◽  
Particle Deformation

scholarly journals Shear Stress-Triggered Deformation of Microparticles in a Tapered Microchannel

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 55
Author(s):  
Cheolheon Park ◽  
Junghyun Bae ◽  
Yeongjae Choi ◽  
Wook Park
Keyword(s):  
Shear Stress ◽  
Void Fraction ◽  
Applied Pressure ◽  
Microfluidic Channel ◽  
Volume Index ◽  
Effective Volume ◽  
Particle Deformation ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Deformation Ratio

We demonstrate that it is possible to produce microparticles with high deformability while maintaining a high effective volume. For significant particle deformation, a particle must have a void region. The void fraction of the particle allows its deformation under shear stress. Owing to the importance of the void fraction in particle deformation, we defined an effective volume index (V*) that indicates the ratio of the particle’s total volume to the volumes of the void and material structures. We chose polyethylene glycol diacrylate (Mn ~ 700) for the fabrication of the microparticles and focused on the design of the particles rather than the intrinsic softness of the material (E). We fabricated microparticles with four distinct shapes: discotic, ring, horseshoe, and spiral, with various effective volume indexes. The microparticles were subjected to shear stress as they were pushed through a tapered microfluidic channel to measure their deformability. The deformation ratio R was introduced as R = 1−Wdeformed/Doriginal to compare the deformability of the microparticles. We measured the deformation ratio by increasing the applied pressure. The spiral-shaped microparticles showed a higher deformation ratio (0.901) than those of the other microparticles at the same effective volume index.

Elastic particle deformation in rectangular channel flow as a measure of particle stiffness

Soft Matter ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Margaret Y. Hwang ◽  
Seo Gyun Kim ◽  
Heon Sang Lee ◽  
Susan J. Muller
Keyword(s):  
Shear Modulus ◽  
Channel Flow ◽  
Rectangular Channel ◽  
Particle Deformation ◽  
Experimental Deformation ◽  
Soft Particles ◽  
Elastic Particle ◽  
Confined Channel

Experimental deformation of hydrogel soft particles in a confined channel is quantified and can be used to obtain shear modulus.

scholarly journals Recent Progress in Processing of Tungsten Heavy Alloys

2014 ◽  
Vol 2014 ◽  
pp. 1-22 ◽  
Author(s):  
Y. Şahin
Keyword(s):  
Microwave Sintering ◽  
High Energy ◽  
Electrical Contacts ◽  
Matrix Composition ◽  
Powder Injection ◽  
Tungsten Particle ◽  
Two Phase ◽  
Heavy Alloys ◽  
Tungsten Heavy Alloys ◽  
Interface Bonding Strength

Tungsten heavy alloys (WHAs) belong to a group of two-phase composites, based on W-Ni-Cu and W-Ni-Fe alloys. Due to their combinations of high density, strength, and ductility, WHAs are used as radiation shields, vibration dampers, kinetic energy penetrators and heavy-duty electrical contacts. This paper presents recent progresses in processing, microstructure, and mechanical properties of WHAs. Various processing techniques for the fabrication of WHAs such as conventional powder metallurgy (PM), advent of powder injection molding (PIM), high-energy ball milling (MA), microwave sintering (MW), and spark-plasma sintering (SPS) are reviewed for alloys. This review reveals that key factors affecting the performance of WHAs are the microstructural factors such as tungsten and matrix composition, chemistry, shape, size and distributions of tungsten particles in matrix, and interface-bonding strength between the tungsten particle and matrix in addition to processing factors. SPS approach has a better performance than those of others, followed by extrusion process. Moreover, deformation behaviors of WHA penetrator and depleted uranium (DU) Ti alloy impacting at normal incidence both rigid and thick mild steel target are studied and modelled as elastic thermoviscoplastic. Height of the mushroomed region is smaller for α=0.3 and it forms sooner in each penetrator as compared to that for α=0.2.

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