Influence of Microparticles and Nanoparticles on the Mechanical Response of Nanostructured Inorganic Polymers

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165641 ◽

1996 ◽

Vol 54 ◽

pp. 636-637

Author(s):

D. L. Callahan

Keyword(s):

Plastic Deformation ◽

Aluminum Nitride ◽

Mechanical Response ◽

Three Dimensional ◽

Bright Field Image ◽

Perfectly Plastic ◽

Contrast Analysis ◽

Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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Revisiting the passivation of stainless steels and other passive CRAs

Matériaux & Techniques ◽

10.1051/mattech/2018020 ◽

2018 ◽

Vol 106 (1) ◽

pp. 107 ◽

Cited By ~ 3

Author(s):

Jean- Louis Crolet

Keyword(s):

Electrical Conductivity ◽

Metal Ions ◽

Base Metal ◽

Stainless Steels ◽

Electronic Conductivity ◽

Transport Processes ◽

General Knowledge ◽

Inorganic Polymers ◽

Faraday Cage

All that was said so far about passivity and passivation was indeed based on electrochemical prejudgments, and all based on unverified postulates. However, due the authors’ fame and for lack of anything better, the great many contradictions were carefully ignored. However, when resuming from raw experimental facts and the present general knowledge, it now appears that passivation always begins by the precipitation of a metallic hydroxide gel. Therefore, all the protectiveness mechanisms already known for porous corrosion layers apply, so that this outstanding protectiveness is indeed governed by the chemistry of transport processes throughout the entrapped water. For Al type passivation, the base metal ions only have deep and complete electronic shells, which precludes any electronic conductivity. Then protectiveness can only arise from gel thickening and densification. For Fe type passivation, an incomplete shell of superficial 3d electrons allows an early metallic or semimetallic conductivity in the gel skeleton, at the onset of the very first perfectly ordered inorganic polymers (- MII-O-MIII-O-)n. Then all depends on the acquisition, maintenance or loss of a sufficient electrical conductivity in this Faraday cage. But for both types of passive layers, all the known features can be explained by the chemistry of transport processes, with neither exception nor contradiction.

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Mechanical Response of Basalt Fiber Asphalt Pavement with Low Temperature-Load Coupling in Heavy Frozen Areas

CICTP 2020 ◽

10.1061/9780784483053.158 ◽

2020 ◽

Author(s):

Hua Wu ◽

Aiqin Shen ◽

Yinchuan Guo ◽

Zhenghua Lyu ◽

Li Fan

Keyword(s):

Low Temperature ◽

Mechanical Response ◽

Asphalt Pavement ◽

Basalt Fiber ◽

Temperature Load

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The Mechanical Response of Aligned Carbon Nanotube Mats via Transmitted Laser Intensity Measurements

10.1557/proc-1142-jj16-04 ◽

2008 ◽

Author(s):

Christian Deck ◽

Chinung Ni ◽

Kenneth Vecchio ◽

Prabhakar Bandaru

Keyword(s):

Carbon Nanotube ◽

Mechanical Response ◽

Laser Intensity ◽

Intensity Measurements

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Surface Modification of Poly (alkyl/Arylphosphazene) Thin Films

MRS Proceedings ◽

10.1557/proc-629-ff9.5 ◽

2000 ◽

Vol 629 ◽

Author(s):

John V. St. John ◽

Patty Wisian-Neilson

Keyword(s):

Thin Films ◽

Surface Modification ◽

Chemical Resistance ◽

Chemical Properties ◽

Inorganic Polymers ◽

Thin Polymer Films ◽

Hydrophilic Interactions ◽

Carboxylic Acid Groups ◽

Polymer Interface ◽

Thin Polymer

ABSTRACTPoly (methylphenylphosphazene) (PMPP) is an example of a unique class of inorganic polymers with alternating – (P=N)– backbones. Chemical modification of bulk PMPP can result in changes of physical properties such as chemical resistance, onset temperature of thermal degradation, elasticity, and flexibility. Surface modification of PMPP allows tailoring of the chemical properties at the polymer interface while maintaining the integrity of the bulk polymer. In this research, PMPP thin films were treated to form carboxylate or carboxylic acid groups at the surface. Surface modification was monitored by following changes in contact angle. The hydrophobic/hydrophilic interactions of carboxylated PMPP surfaces allow for mesoscale interactions of thin polymer films.

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