scholarly journals Microstructure and mechanical properties of 3D Cf/SiBCN composites fabricated by polymer infiltration and pyrolysis

2020 ◽  
Author(s):  
Bowen Chen ◽  
Qi Ding ◽  
De-Wei Ni ◽  
Hongda Wang ◽  
Yusheng Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Cross Link ◽  
Ceramic Yield ◽  
Liquid Precursor ◽  
X Ray ◽  
3D Microstructure ◽  
Crosslinking Process ◽  
X Ray Computed ◽  
Polymer Infiltration

Abstract In this work, 3D C f /SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced x-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution and mechanical properties of the composites were uncovered. With the addition of DCP initiator, the liquid precursor can cross-link to solid-state at 120 °C. Moreover, DCP addition decreases the release of small molecule gas during pyrolysis, leading to an improved ceramic yield 4.67 times higher than that without DCP addition. After 7 PIP cycles, density and open porosity of the final Cf/SiBCN composite with DCP addition are 1.73 g·cm -3 and ~10%, respectively, which are 143.0% higher and 30.3% lower compared with the composites without DCP addition. As a result, the flexural strength and elastic modulus of Cf/SiBCN composites with DCP addition (371 MPa and 31 GPa) are 1.74 and 1.60 times higher than that without DCP addition (213 MPa and 19.4 GPa).

scholarly journals Microstructure and mechanical properties of 3D Cf/SiBCN composites fabricated by polymer infiltration and pyrolysis

2020 ◽  
Author(s):  
Bowen Chen ◽  
Qi Ding ◽  
De-Wei Ni ◽  
Hongda Wang ◽  
Yusheng Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Cross Link ◽  
Ceramic Yield ◽  
Liquid Precursor ◽  
X Ray ◽  
3D Microstructure ◽  
Crosslinking Process ◽  
X Ray Computed ◽  
Polymer Infiltration

Abstract In this work, 3D Cf/SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced x-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution and mechanical properties of the composites were uncovered. With the addition of DCP initiator, the liquid precursor can cross-link to solid-state at 120 °C. Moreover, DCP addition decreases the release of small molecule gas during pyrolysis, leading to an improved ceramic yield 4.67 times higher than that without DCP addition. After 7 PIP cycles, density and open porosity of the final Cf/SiBCN composite with DCP addition are 1.73 g·cm-3 and ~10%, respectively, which are 143.0% higher and 30.3% lower compared with the composite without DCP addition. As a result, the flexural strength and elastic modulus of Cf/SiBCN composites with DCP addition (371 MPa and 31 GPa) are 1.74 and 1.60 times higher than that without DCP addition (213 MPa and 19.4 GPa).

scholarly journals Microstructure and mechanical properties of 3D Cf/SiBCN composites fabricated by polymer infiltration and pyrolysis

2020 ◽  
Author(s):  
Bowen Chen ◽  
Qi Ding ◽  
Dewei Ni ◽  
Hongda Wang ◽  
Yusheng Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Three Dimensional ◽  
Cross Linking ◽  
Ceramic Yield ◽  
X Ray ◽  
3D Microstructure ◽  
Crosslinking Process ◽  
X Ray Computed ◽  
Polymer Infiltration

AbstractIn this work, three-dimensional (3D) Cf/SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced X-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution, and mechanical properties of the composites were uncovered. With the addition of a DCP initiator, the liquid precursor can cross-linking to solid-state at 120 °C. Moreover, DCP addition decreases the release of small molecule gas during pyrolysis, leading to an improved ceramic yield 4.67 times higher than that without DCP addition. After 7 PIP cycles, density and open porosity of the final Cf/SiBCN composite with DCP addition are 1.73 g·cm−3 and ∼10%, respectively, which are 143.0% higher and 30.3% lower compared with the composites without DCP addition. As a result, the flexural strength and elastic modulus of Cf/SiBCN composites with DCP addition (371 MPa and 31 GPa) are 1.74 and 1.60 times higher than that without DCP addition (213 MPa and 19.4 GPa), respectively.

Preliminary Application of X-ray Computed Tomograph on Characterisation of Polish Gas Shale Mechanical Properties

2016 ◽  
Vol 49 (12) ◽  
pp. 4935-4943 ◽  
Author(s):  
M. Cała ◽  
K. Cyran ◽  
A. Stopkowicz ◽  
M. Kolano ◽  
M. Szczygielski
Keyword(s):  
Mechanical Properties ◽  
Gas Shale ◽  
X Ray ◽  
X Ray Computed ◽  
Computed Tomograph ◽  
Preliminary Application

scholarly journals Effect of Porosity on Mechanical Properties of 3D Printed Polymers: Experiments and Micromechanical Modeling Based on X-Ray Computed Tomography Analysis

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1154 ◽  
Author(s):  
Wang ◽  
Zhao ◽  
Fuh ◽  
Lee
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Micromechanical Model ◽  
Micromechanical Modeling ◽  
X Ray ◽  
Fused Deposition ◽  
3D Printed ◽  
X Ray Computed

Additive manufacturing (commonly known as 3D printing) is defined as a family of technologies that deposit and consolidate materials to create a 3D object as opposed to subtractive manufacturing methodologies. Fused deposition modeling (FDM), one of the most popular additive manufacturing techniques, has demonstrated extensive applications in various industries such as medical prosthetics, automotive, and aeronautics. As a thermal process, FDM may introduce internal voids and pores into the fabricated thermoplastics, giving rise to potential reduction on the mechanical properties. This paper aims to investigate the effects of the microscopic pores on the mechanical properties of material fabricated by the FDM process via experiments and micromechanical modeling. More specifically, the three-dimensional microscopic details of the internal pores, such as size, shape, density, and spatial location were quantitatively characterized by X-ray computed tomography (XCT) and, subsequently, experiments were conducted to characterize the mechanical properties of the material. Based on the microscopic details of the pores characterized by XCT, a micromechanical model was proposed to predict the mechanical properties of the material as a function of the porosity (ratio of total volume of the pores over total volume of the material). The prediction results of the mechanical properties were found to be in agreement with the experimental data as well as the existing works. The proposed micromechanical model allows the future designers to predict the elastic properties of the 3D printed material based on the porosity from XCT results. This provides a possibility of saving the experimental cost on destructive testing.

Modeling the Properties of Cellular Ceramics: From Foams to Lattices and Back to Foams

2014 ◽  
Vol 91 ◽  
pp. 70-78 ◽  
Author(s):  
Alberto Ortona ◽  
Ehsan Rezaei
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Replica Method ◽  
Harsh Environments ◽  
Morphological Parameters ◽  
Element Analysis ◽  
Ceramic Foams ◽  
X Ray ◽  
X Ray Computed

Cellular ceramics are attracting material solutions for high temperature applications because of their outstanding properties. SiC cellular ceramics in particular withstand harsh environments at high temperatures for long operating times and are particularly resistant to thermal shock. Ceramic foams though, being random fragile structures, comprise properties which are rather scattered and difficult to engineer. This presentation shows how finite element analysis is used to study the effect of morphological features on ceramic foams in respect of their mechanical properties. Mean morphological parameters, obtained by X-ray computed tomography (XCT) on a commercially available SiSiC foam produced by the replica method, were used to generate a set of lattices in which one parameter was varied at a time. Starting from this approach, further work was then dedicated to optimize their properties. Polymeric lattices and foams, in which some characteristics were digitally modified learning from the optimization work were, produced by 3D printing and ceramized via the replica method. Both foams and lattices were then mechanically tested. Results show that some features such as strut shape and cell stretching affect the mechanical behavior of ceramic foams.

scholarly journals Microstructural differences between naturally-deposited and laboratory beach sands

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Amy Ferrick ◽  
Vanshan Wright ◽  
Michael Manga ◽  
Nicholas Sitar
Keyword(s):  
Mechanical Properties ◽  
Coordination Number ◽  
Grain Orientation ◽  
Flowing Water ◽  
X Ray ◽  
Depositional Processes ◽  
Grain Orientations ◽  
Computed Microtomography ◽  
X Ray Computed ◽  
Beach Sands

AbstractThe orientation of, and contacts between, grains of sand reflect the processes that deposit the sands. Grain orientation and contact geometry also influence mechanical properties. Quantifying and understanding sand microstructure thus provide an opportunity to understand depositional processes better and connect microstructure and macroscopic properties. Using x-ray computed microtomography, we compare the microstructure of naturally-deposited beach sands and laboratory sands created by air pluviation in which samples are formed by raining sand grains into a container. We find that naturally-deposited sands have a narrower distribution of coordination number (i.e., the number of grains in contact) and a broader distribution of grain orientations than pluviated sands. The naturally-deposited sand grains orient inclined to the horizontal, and the pluviated sand grains orient horizontally. We explain the microstructural differences between the two different depositional methods by flowing water at beaches that re-positions and reorients grains initially deposited in unstable grain configurations.

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