Porous Ti6Al4V alloys with high strength-to-modulus ratio fabricated by unidirectional freeze casting of SiC fiber-containing slurry

2021 ◽  
pp. 141584
Author(s):  
Fuping Li ◽  
Tao Jia ◽  
Wei Dang ◽  
Zhuoli Xu ◽  
Kang Zhao ◽  
...  
Keyword(s):  
High Strength ◽  
Freeze Casting ◽  
Modulus Ratio ◽  
Sic Fiber

Strong Interface in CMCs, a Condition for Efficient Multilayered Interphases

1994 ◽  
Vol 365 ◽  
Author(s):  
Christine Droillard ◽  
Jacques Lamon ◽  
Xavier Bourrat
Keyword(s):  
Fracture Toughness ◽  
Bonding Strength ◽  
High Strength ◽  
Interfacial Behavior ◽  
Strain Behavior ◽  
High Toughness ◽  
Sic Fiber ◽  
Sliding Mechanism ◽  
Fiber Treatment ◽  
Sic Composites

ABSTRACTA fiber treatment was used to change the bonding strength of the Nicalon NLM 202 SiC fiber from weak to strong, in a series of 2D-SiC/SiC composites with multilayered interphases. The materials with the pre-treated fibers were compared to the same materials but reinforced with as received fibers. The stress-strain behavior and the fracture toughness were examined as a function of crack patterns identified by TEM. All the materials could be grouped into two distinct families: (i) materials reinforced with untreated fibers have a weak fiber bonding and are characterized by a low strength and a low toughness and (2) materials with the pre-treated fibers have a strong fiber bonding and are characterized by a high strength and a high toughness. This latter behavior is identified by TEM. It corresponds to a new interfacial behavior with a cohesive mode of interfacial cracking, involving branching and deflection by the successive interfaces. In the former family, the adhesive interfacial failure mode corresponds to the classical debond/sliding mechanism.

The role of CuO–TiO2 additives in the preparation of high-strength porous alumina scaffolds using directional freeze casting

2015 ◽  
Vol 23 (2) ◽  
pp. 539-547 ◽  
Author(s):  
Yujie Fu ◽  
Ping Shen ◽  
Zhijie Hu ◽  
Chang Sun ◽  
Ruifen Guo ◽  
...  
Keyword(s):  
Porous Alumina ◽  
High Strength ◽  
Freeze Casting

scholarly journals The Effect of Excess Carbon on the Crystallographic, Microstructural, and Mechanical Properties of CVD Silicon Carbide Fibers

2006 ◽  
Vol 982 ◽  
Author(s):  
James V Marzik ◽  
William J. Croft ◽  
Richard J. Staples ◽  
Warren J. MoberlyChan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Silicon Carbide ◽  
Elastic Modulus ◽  
Chemical Vapor ◽  
High Strength ◽  
Excess Carbon ◽  
X Ray ◽  
Silicon Carbide Fibers ◽  
Sic Fiber

ABSTRACTSilicon carbide (SiC) fibers made by chemical vapor deposition (CVD) are of interest for organic, ceramic, and metal matrix composite materials due their high strength, high elastic modulus, and retention of mechanical properties at elevated processing and operating temperatures. The properties of SCS-6™ silicon carbide fibers, which are made by a commercial process and consist largely of stoichiometric SiC, were compared with an experimental carbon-rich CVD SiC fiber, to which excess carbon was added during the CVD process. The concentration, homogeneity, and distribution of carbon were measured using energy dispersive x-ray spectroscopy (SEM/EDS). The effect of excess carbon on the tensile strength, elastic modulus, and the crystallographic and microstructural properties of CVD silicon carbide fibers was investigated using tensile testing, x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

High-strength porous Si 3 N 4 ceramics prepared by freeze casting and silicon powder nitridation process

2014 ◽  
Vol 133 ◽  
pp. 285-288 ◽  
Author(s):  
Hai-Long Hu ◽  
Yu-Ping Zeng ◽  
Yong-Feng Xia ◽  
Dong-Xu Yao ◽  
Kai-Hui Zuo
Keyword(s):  
High Strength ◽  
Silicon Powder ◽  
Freeze Casting ◽  
Porous Si ◽  
Nitridation Process

Effect of Electrochemical Treatment on the Surface Structure and Tensile Strength of Carben Coated CVD SiC Fiber

2007 ◽  
Vol 546-549 ◽  
pp. 1571-1574
Author(s):  
L. Ji ◽  
N.L. Shi ◽  
Rui Yang
Keyword(s):  
Tensile Strength ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Stability ◽  
High Strength ◽  
Electrochemical Treatment ◽  
X Ray ◽  
Sic Fiber ◽  
Carbon Coated ◽  
Anodic Oxidation Method

CVD (chemical vapor deposition) SiC continuous fiber is used as reinforcement of metal matrix composites because of its high strength, high stiffness and elevated temperature stability. In this work, anodic oxidation method was used to treat the surface of carbon coated SiC fiber. Then the surface of treated fiber was compared with untreated one by scan electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). SiC was detected on the surface of untreated carbon-rich coating. It is proved by XPS that SiC was transformed into SiO2 after treatment. About 100~200nm thick oxidation layer was detected on the surface of carbon-rich coating and the structure of double coatings formed. Because the surface of fiber became smooth and the tensile stress on it was relaxed after treatment, the tensile strength of fiber was improved by 8%~20% average and the dispersing ratio of it was reduced.

scholarly journals Electron Beam Melted Beta-type Ti–24Nb–4Zr–8Sn Porous Structures With High Strength-to-Modulus Ratio

2016 ◽  
Vol 32 (6) ◽  
pp. 505-508 ◽  
Author(s):  
Yujing Liu ◽  
Shujun Li ◽  
Wentao Hou ◽  
Shaogang Wang ◽  
Yulin Hao ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Strength ◽  
Porous Structures ◽  
Modulus Ratio

Development of Ultrafine Piercing By SiC Fiber Punch

2004 ◽  
Vol 126 (4) ◽  
pp. 659-665 ◽  
Author(s):  
Toshihiko Mori
Keyword(s):  
Aspect Ratio ◽  
Strong Dependence ◽  
High Strength ◽  
Aluminum Foil ◽  
Material Behavior ◽  
Punch Force ◽  
Sic Fiber ◽  
Punching Process ◽  
And Performance ◽  
Metallic Foils

An integrated micropress was developed for ultrafine piercing of metallic foils by a SiC fiber punch. The fiber punch was produced by a series of processes that use buffing and electrolysis operations. The technology incorporates unique tooling and fixturing techniques to handle delicate pinholes, apertures, collimators, and air slits to allow a repeatable manufacturing process with minimal part handling. Since the diagnostic pinholes may be very thin or small in size, it is critical that there is minimal human intervention from the start to the final process of the piercing operation. Selection of materials, design of the integrated micropress, and performance of the system are discussed in detail. The performance of the technique was tested on three kinds of metal foils that have various thickness and strength. A 17-μm-thick aluminum foil was tested as an example of a high aspect ratio and low strength, a 15-μm-thick beryllium copper for a high strength, and an 8 μm stainless steel for a hard-to-form materials. Observations of the scanning electron microscope show that every hole was truly round with the sheared surface being smooth and burr free. Based on the measurements of the punch force and punch stroke, the material behavior in the ultrafine piercing process resembled that of the normal punching process, with a strong dependence on the material properties and the aspect ratio. The SiC fiber was found to be a secure ultrafine punch, with sufficient strength that can produce truly round holes particularly in smaller sizes.

scholarly journals Numerical Simulation for Elasto-Plastic Contact of Novel Ti-(SiCf/Al3Ti)-Laminated Composite with Double-Layered SiC Fiber Reinforcements

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 165 ◽  
Author(s):  
Jingchuan Liu ◽  
Mengqi Zhang ◽  
Fengchun Jiang ◽  
Lan Zhang ◽  
Liquan Wang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Volume Fraction ◽  
Fiber Diameter ◽  
Energy Dispersive Spectrometer ◽  
Laminated Composite ◽  
High Strength ◽  
Material Strength ◽  
Sic Fiber ◽  
Equivalent Inclusion Method ◽  
Deformation Behaviors

An innovative, high-strength metal–intermetallic-laminate (MIL) composite Ti-(SiCf/Al3Ti), reinforced by double or even several SiC fiber rows, was fabricated. A high-efficiency, semi-analytical model with a numerical equivalent inclusion method (NEIM) was employed to investigate the deformation behaviors, microscopic strengthening, and failure mechanisms of the composite during elasto-plastic sphere–plane contact. The microstructure and interface features were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The contact model for the Ti-(SiCf/Al3Ti) composite was validated via quasi-static compressive indentation tests with a spherical indenter. A series of in-depth parametric studies were conducted to quantify the effect of the microstructure. The results indicate that the as-fabricated laminated composite has a well-organized microstructure and a higher volume fraction of fibers. The SiC fiber rows effectively enhance the strength and toughness of the composite. The optimal diameter of the SiC fibers is 32 μm when the horizontal center distance between the adjacent fibers is 2.5 times that of the fiber diameter. The hole defects occurring above the fibers would damage the material strength most compared with those occurring in other positions. The optimal quantity of the SiC fiber rows is four when the thickness of the SiCf/Al3Ti layer is 400 μm and the fiber diameter is 8 μm.

Microstructural Investigation of Strength Degradation in A Developmental Cvd Sic Fiber At 2000° C

1997 ◽  
Vol 3 (S2) ◽  
pp. 743-744
Author(s):  
A. Garg ◽  
D. R. Hull ◽  
R. T. Bhatt
Keyword(s):  
Fiber Strength ◽  
Chemical Vapor ◽  
High Strength ◽  
Pyrolytic Carbon ◽  
Microstructural Investigation ◽  
Sic Fibers ◽  
Sic Fiber ◽  
Heat Treated ◽  
Carbon Coated ◽  
Increasing Demand

SiC fibers fabricated by chemical vapor deposition (CVD) methods are being used as reinforcement for metal and ceramic matrix materials because of their high modulus, high strength and good corrosion resistance. These fibers have a complex composite microstructure consisting of a pyrolytic-carbon coated graphite core and a SiC sheath which is often protected by a single or a double layer of carbon-rich coating. Commercially available SCS-6 SiC fibers with a diameter of ˜ 140 μm have been most widely in use for composite fabrication. However, with an ever increasing demand for thinner and stronger fibers, an experimental SiC fiber with a diameter of ˜ 50 μm and having a C-rich SiC sheath was developed by Textron Specialty Materials. The as-fabricated tensile strength of this fiber was found to be ˜ 6 GPa, which is ˜ 50 % higher than that of the SCS-6 fiber.While the room temperature tensile strengths of these fibers heat treated for 1 h in Ar to temperatures ≤ 1600° C were better than those of the SCS-6 fiber, strength of the 2000° C heated fibers decreased to < 1 GPa.

Analysis on the Zoning and Initial Elastic Modulus of Main and Secondary Rock-Fill of CFRD Deformation

2011 ◽  
Vol 52-54 ◽  
pp. 601-605 ◽  
Author(s):  
Jian Mao ◽  
Zheng Zhong Wang ◽  
Quan Hong Liu ◽  
Xiao Kong Yu
Keyword(s):  
Elastic Modulus ◽  
Soft Rock ◽  
High Strength ◽  
Boundary Line ◽  
Elastic Model ◽  
Modulus Ratio ◽  
Rock Fill ◽  
Dam Deformation ◽  
Strength Rock ◽  
Nonlinear Elastic

Based on Duncan-zhang nonlinear elastic model and ANSYS software, impacts on the settlement and stress of dam as well as the panel deflection are studied with different modulus of dam embankment materials and zoning of rock-fill dams. Through a variety of comparisons, the result shows that the dam settlement and the maximum deflection of panels increase as the initial elastic modulus ratio of main to secondary rock-fill rising. The ratio was much more reasonable within 1 - 2 and the dam deformation was small; 0.3 times top of the dam filled with high strength rock-fill materials might decrease settlement and panel deflection. The boundary line could be put forward to upstream appropriately to improve the utilization of soft rock with modulus ratio of main to secondary rock-fill less than 1.5 times.

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