Preparation and Properties of Hot Pressed 2D C/SiC Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1047-1049
Author(s):  
Hai Feng Hu ◽  
Feng Zhang ◽  
Qi Kun Wang ◽  
Yu Di Zhang ◽  
Zhao Hui Chen
Keyword(s):  
Carbon Fibers ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Holding Time ◽  
Maximum Strength ◽  
Carbon Powder ◽  
Optimum Processing ◽  
Sic Composites ◽  
Transfer Pressure

In this paper a pseudo-HP process, which uses solid powder to transfer pressure to prepare complex shape articles, was adopted to prepare 2D C/SiC composites. Nano-SiC powder was used to lower the sintering temperature, thus decreasing the damage to carbon fibers. The optimum processing parameters are as follows: sintering temperature 1850°C, holding time 60min, sintering pressure 10MPa. The maximum strength is over 300MPa, and toughness is around 8MPa·m1/2. BN powder is more lubricous than carbon powder, and thus is more convenient for demoulding and pressure transferring. Precursor Infiltration and Pyrolysis (PIP) was used to further densify the composites after HP process, and strength and toughness of the samples were slightly enhanced.

Effects of Processing Parameters of SPS on the Densification and Texture of LaPO4 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1059-1061 ◽  
Author(s):  
Ai Bing Du ◽  
Zhi Xue Qu ◽  
Chun Lei Wan ◽  
Ruo Bing Han ◽  
Wei Pan
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Preferred Orientation ◽  
Holding Time ◽  
Plasma Sintering ◽  
Spark Plasma

Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.

Simulation Research of the Effect of Thermal Reflow Processing Parameters on the Profile of Micro-Spherical Structure

2011 ◽  
Vol 239-242 ◽  
pp. 517-523 ◽  
Author(s):  
Bing Yan Jiang ◽  
Lei Chen ◽  
Dai Bing Li ◽  
Stefan Kirchberg
Keyword(s):  
Heating Rate ◽  
Heating Temperature ◽  
Orthogonal Experiment ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Holding Time ◽  
Cylindrical Shape ◽  
Optimum Processing ◽  
Spherical Structure ◽  
Experiment Method

In this paper reflow process is integrated into LIGA process in order to realize three dimensional fabrication. The melting and deformation process of photoresist, which has an initial cylindrical shape of D500μm and h66μm, and the influence of various processing parameters on the height of formed microlens, is simulated with Marc. The optimum processing parameters combination is obtained by orthogonal experiment method and the influence of different processing parameters on the height of micro-spherical structure is studied with single factor experiment method. The results showed that the optimum processing parameters combination was 1°C /s for heating rate, 110°C for heating temperature and 45min for holding time; the significance of processing parameters on the micro-spherical structure’s height can be ordered in holding time＞heating rate＞heating temperature.

scholarly journals Microstructure Evolution and Properties of an In-Situ Nano-Gd2O3/Cu Composite by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5021
Author(s):  
Haiyao Cao ◽  
Zaiji Zhan ◽  
Xiangzhe Lv
Keyword(s):  
Tensile Strength ◽  
Powder Metallurgy ◽  
Load Transfer ◽  
Sintering Temperature ◽  
Copper Matrix ◽  
Processing Parameters ◽  
Holding Time ◽  
Matrix Composites ◽  
Transmission Electron ◽  
Mean Size

Gadolinia (Gd2O3) is potentially attractive as a dispersive phase for copper matrix composites due to its excellent thermodynamic stability. In this paper, a series of 1.5 vol% nano-Gd2O3/Cu composites were prepared via an internal oxidation method followed by powder metallurgy in the temperature range of 1123–1223 K with a holding time of 5–60 min. The effects of processing parameters on the microstructure and properties of the composites were analyzed. The results showed that the tensile strength and conductivity of the nano-Gd2O3/Cu composite have a strong link with the microporosity and grain size, while the microstructure of the composite was determined by the sintering temperature and holding time. The optimal sintering temperature and holding time for the composite were 1173 K and 30 min, respectively, under which a maximum ultimate tensile strength of 317 MPa was obtained, and the conductivity was 96.8% IACS. Transmission electron microscopy observations indicated that nano-Gd2O3 particles with a mean size of 76 nm formed a semi-coherent interface with the copper matrix. In the nano-Gd2O3/Cu composite, grain-boundary strengthening, Orowan strengthening, thermal mismatch strengthening, and load transfer strengthening mechanisms occurred simultaneously.

scholarly journals Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

2021 ◽  
Vol 13 (12) ◽  
pp. 6739
Author(s):  
Darko Landek ◽  
Lidija Ćurković ◽  
Ivana Gabelica ◽  
Mihone Kerolli Mustafa ◽  
Irena Žmak
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Nonlinear Models ◽  
Slip Casting ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Aqueous Suspensions ◽  
Temperature Heating

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

scholarly journals Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Low Cost ◽  
Deposition Process ◽  
Processing Parameters ◽  
Yarn Diameter ◽  
Thermoplastic Matrix ◽  
Anisotropic Mechanical Properties ◽  
Long Carbon Fiber

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

Effects of Direct Thermal Method Processing Parameters on Mechanical Properties of Semisolid A6061 Feedstock

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
M. F. M. Tajudin ◽  
A. H. Ahmad ◽  
M. M. Rashidi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Room Temperature ◽  
Processing Parameters ◽  
Holding Time ◽  
Thermal Method ◽  
Pouring Temperature ◽  
Porosity Level ◽  
Experimental Works ◽  
Temperature Water

This paper highlights the effects of pouring temperature and holding time on the mechanical properties of aluminium 6061 semisolid feedstock billets. The semisolid metal feedstock billets were prepared by a direct thermal method (DTM), in which the molten metal was poured into a cylindrical copper mould with a different combination of pouring temperature and holding time before it was solidified in room temperature water. The results show that the sample with pouring temperature slightly above aluminium 6061 liquidus temperature has the lowest porosity, thereby the highest mechanical properties value. The sample with a pouring temperature of 660 °C and holding time of 60 s has the density, tensile strength and hardness properties of 2.701 g/cm3, 146.797 MPa, and 86.5 HV, respectively. Meanwhile, the sample at a pouring temperature of 640 °C and holding time of 20 s has density, tensile strength and hardness properties of 2.527 g/cm3, 65.39 MPa, and 71.79 HV, respectively. The density and fractography tests were conducted to confirm the existence of porosity within the samples. The results from these experimental works suggested that the mechanical properties of DTM semisolid feedstock billet merely depended on processing parameters, which influenced the porosity level within the feedstock billet, thus directly affected their mechanical properties.

Effect of Processing Parameters on Mechanical Properties of Al7175/Boron Carbide (B4C) Composite Fabricated by Powder Metallurgy Techniques

2021 ◽  
Vol 105 ◽  
pp. 8-16
Author(s):  
Guttikonda Manohar ◽  
Krishna Murari Pandey ◽  
Saikat Ranjan Maity
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Powder Metallurgy ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Matrix Composites ◽  
Composite Powders ◽  
Porosity Level ◽  
Milling Operations ◽  
Boron Carbide B4c

Metal matrix composites attain a significant position in Industrial, defense, structural and automobile applications. To amplify that strategy there is a need to find out the conditional behavior of the composites and enhancing the properties will be mandatory. The present work mainly investigates on the effect of processing parameters like densification rates, sintering temperature, reinforcement content on the microstructure, mechanical properties of the Al7175/B4C composite material fabricated by mechanical milling and powder metallurgy techniques. Results show there is a grain size reduction and refinement in the composite material through ball milling operations and along with that increasing B4C content in the composite powders make milling conditions very effective. Increasing the sintering temperature results in a consistent grain growth along with that porosity level decreases up to a limit and then attain a steady state, the strength of the composites increases with compaction pressures but reinforcements content effects the strength of the material by losing its ductility making it brittle.

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