Precipitate phases in an Al-SiC composite

1984 ◽  
Vol 42 ◽  
pp. 490-491
Author(s):  
S.R. Nutt ◽  
R.W. Carpenter
Keyword(s):  
Fracture Toughness ◽  
Composite Material ◽  
Alloy Powder ◽  
Heat Treating ◽  
Matrix Alloy ◽  
Al Alloy ◽  
Unreinforced Alloy ◽  
The Matrix ◽  
Sic Whiskers ◽  
Sic Composites

The modulus of many aluminum alloys can be greatly increased by the addition of small amounts of silicon carbide. The resulting composite material is also stronger than the unreinforced alloy, but exhibits poor fracture toughness. The reason for the low ductility of Al-SiC composites is unknown, although results presented here indicate that embrittling phases present in the matrix alloy may be partially responsible. The purpose of this work has been to study the distribution of precipitate phases in Al-SiC composites, focusing particular attention on interface regions. The material studied was fabricated by adding SiC whiskers to a 2124 Al alloy powder, consolidating, then heat treating to a T6 temper.

Whisker Orientation Measurements in Injection Molded Si3N4-SiC Composites

1988 ◽  
Author(s):  
J. T. Neil ◽  
D. A. Norris
Keyword(s):  
Fracture Toughness ◽  
Composite Material ◽  
Silicon Nitride ◽  
Aspect Ratio ◽  
Injection Molding ◽  
Hot Isostatic Pressing ◽  
Sem Micrographs ◽  
Sic Whiskers ◽  
Injection Molded ◽  
Sic Composites

Hot pressed composites of Si3N4 containing 30% SiC whiskers have shown substantial improvements in strength and fracture toughness relative to monolithic silicon nitride. Injection molded samples made of this composite material distorted in a systematic manner during densification by hot isostatic pressing. Whisker orientation and aspect ratio measurements based on digitized SEM micrographs were used to evaluate microstructure with respect to injection molding direction. Results show definite orientation of whiskers during injection molding which can be related to the observed densification distortion.

scholarly journals Particularities of structure formation of aluminum-copper composite materials manufactured by casting technology

2020 ◽  
pp. 116-121
Author(s):  
V. A. Kalinichenko ◽  
A. S. Kalinichenko ◽  
S. V. Grigoriev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Structure Formation ◽  
Matrix Material ◽  
Matrix Alloy ◽  
Alloying Elements ◽  
Casting Technology ◽  
The Matrix ◽  
Reinforcing Material ◽  
Copper Composite

To create friction pairs operating in severe working conditions, composite materials are now increasingly used. Composite materials obtained with the use of casting technologies are of interest due to the possibility to manufacture wide range of compositions at low price compared to powder metallurgy. Despite the fact that many composite materials have been sufficiently studied, it is of interest to develop new areas of application and give them the properties required by the consumer. In the present work the composite materials on the basis of silumin reinforced with copper granules were considered. Attention was paid to the interaction between the matrix alloy and the reinforcing phase material as determining the properties of the composite material. The analysis of distribution of the basic alloying elements in volume of composite material and also in zones of the interphases interaction is carried out. The analysis of the possibility of obtaining a strong interphase zone of contact between the reinforcing component and the matrix material without significant dissolution of the reinforcing material is carried out.

scholarly journals Fracture Toughness Improvement of Poly(lactic acid) Reinforced with Poly(ε-caprolactone) and Surface-Modified Silicon Carbide

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jie Chen ◽  
Tian-Yi Zhang ◽  
Fan-Long Jin ◽  
Soo-Jin Park
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Lactic Acid ◽  
Poly Lactic Acid ◽  
External Energy ◽  
Solution Blending ◽  
Blending Method ◽  
Sic Whiskers ◽  
Sic Composites ◽  
Surface Modified

In this study, bio-based poly(lactic acid) (PLA)/polycaprolactone (PCL) blends and PLA/PCL/silicon carbide (SiC) composites were prepared using a solution blending method. The surface of the SiC whiskers was modified using a silane coupling agent. The effects of the PCL and SiC contents on the flexural properties, fracture toughness, morphology of PLA/PCL blends, and PLA/PCL/SiC composites were investigated using several techniques. Both the fracture toughness and flexural strength of PLA increased by the introduction of PCL and were further improved by the formation of SiC whiskers. Fracture surfaces were observed by scanning electron microscopy, which showed that the use of PCL as a reinforcing agent induces plastic deformation in the PLA/PCL blends. The SiC whiskers absorbed external energy because of their good interfacial adhesion with the PLA matrix and through SiC-PLA debonding in the PLA/PCL/SiC composites.

Investigation of the influence of the properties of wood filler on the fracture toughness of the composite material

10.12737/6291 ◽  
2014 ◽  
Vol 4 (3) ◽  
pp. 213-219 ◽  
Author(s):  
Стородубцева ◽  
Tamara Storodubtseva ◽  
Аскомитный ◽  
Aleksey Askomitnyy
Keyword(s):  
Fracture Toughness ◽  
Composite Material ◽  
Current Trend ◽  
Environmental Safety ◽  
Physical Factors ◽  
Principal Stresses ◽  
Resource Saving ◽  
Advantages And Disadvantages ◽  
The Matrix ◽  
Manufacturing Techniques

Current trend in the last decade is the creation of resource-saving technology for production of composite materials. Purpose of the research, the results of which are presented in this paper is to develop on the basis of their material science, technology and other methods to ensure fracture toughness of the composite material on the basis of the waste timber for a predetermined period of operation of products, including railway sleepers, collapsible panels for forest transportation roads. The results of theoretical and experimental research to identify the influence of physical factors on the fracture toughness, the monolithic of structure of the composite material are given measures to protect it from the action of water are considered. The analysis of the two variants of stress and strain state in a cube of wood was made, the value of the principal stresses are found, through the direction, cosines of position of the main provisions are defined, and then the principal values of the relative deformations. An experiment to detect resistance of specimens of composite beams of the base composition, immersed in water was hold, which are then tested in pure bending. The advantages and disadvantages of the possible components of polymer matrix KM on the basis of wood were considered from positions of including them into its structure in order to increase water resistance, limiting tensile strength and environmental safety. The substantiation of the choice of the components of water-resistant composition of the matrix of the composite was given and the manufacturing techniques of its products for the transportation construction - railway sleepers, for example, in the existing shops of sleep-cutting; prefabricated slabs for logging roads is developed.

Elevated Temperature Neutron Measurements of Thermal Residual Stresses in a Sic Fibre Reinforced Al Alloy

1994 ◽  
Vol 376 ◽  
Author(s):  
Monica Ceretti ◽  
M. Kocsis ◽  
A. Lodini
Keyword(s):  
Residual Stresses ◽  
Al Alloy ◽  
Thermal Residual Stresses ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
The Matrix ◽  
Al 7075 ◽  
Sic Whiskers ◽  
Stress Free State ◽  
Increasing Temperature

ABSTRACTThe main objective of the present investigation is to determine the evolution of residual stresses by neutron powder diffraction in an Al/SiC composite (Al 7075 reinforced by 27 vol.% SiC whiskers), originating from thermal treatment and mechanical loading. The results show that residual stresses in the matrix and in the reinforcement decrease in magnitude with increasing temperature and they reach the stress free state at the 'equivalent temperature'. As the temperature further increases, these stresses increase numerically in a reverse sense for both phases. The data obtained are analysed in terms of a simple model based on Eshelby's equivalent inclusion method.

Characterization of Fracture Toughness of Hybrid MMCs the Short Fiber Reinforced Metal Matrix Composites

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1827-1832
Author(s):  
Moon Sik Han ◽  
Jung Il Song
Keyword(s):  
Fracture Toughness ◽  
Metal Matrix Composites ◽  
Dynamic Fracture ◽  
Metal Matrix ◽  
Matrix Alloy ◽  
Short Fiber ◽  
Dynamic Fracture Toughness ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
The Matrix

Evaluation of fracture toughness of short fiber reinforced metal matrix composites (MMCs) becomes important for the application as structural materials. Therefore, in this study static and dynamic fracture toughness of MMCs manufactured by squeeze casting process were investigated. A number of MMCs have been tested with various matrix alloys, volume fractions, and specifically types of reinforcements. It was found that static and dynamic fracture toughness of metal matrix composites was remarkably decreased by the addition of ceramic reinforcements. Dynamic fracture toughness slightly decreased compared with static fracture toughness because of the effect of dynamic velocity under impact loading. The toughness of ceramic reinforced MMCs is controlled by a complexity interaction between the matrix alloy and reinforcement. Important properties which influence toughness include the type of reinforcement (its physical form, size), volume fraction and combination of reinforcement, and the matrix alloy. And notch fracture toughness of MMCs for simple evaluation was also discussed.

Strain contrast in SiC whisker reinforced Al2O3

1986 ◽  
Vol 44 ◽  
pp. 498-499
Author(s):  
P. Angelini ◽  
W. Mader
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Thermal Expansion ◽  
Quantitative Analysis ◽  
Residual Stresses ◽  
Strain Field ◽  
Ceramic Materials ◽  
Spherical Particles ◽  
The Matrix ◽  
Sic Whiskers

Whisker reinforced ceramic materials offer the potential for increased fracture toughness and fracture strength. Residual stresses resulting from differences in thermal expansion properties of the matrix and the whisker can develop during cooling and affect mechanical properties. TEH strain contrast of large inclusions has previously been observed for nearly spherical particles of ZrO2 in Al2O3 matrix grains. The formation of strain contrast oscillations was explained and a quantitative analysis of strains around ZrO2 inclusions in Al2O3 was performed. The present research is concerned with characterizing by TEM the strain field present in Al2O3 reinforced with SiC whiskers.

Preparation and Flame Ablation/Oxidation Behavior of ZrB2/SiC Ultra-High Temperature Ceramic Composites

2007 ◽  
Vol 351 ◽  
pp. 142-146 ◽  
Author(s):  
Chang An Wang ◽  
Hai Long Wang ◽  
Yong Huang ◽  
Dai Ning Fang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Thermal Ablation ◽  
Oxidation Behavior ◽  
Ceramic Composites ◽  
Argon Atmosphere ◽  
Good Resistance ◽  
Sic Ceramic ◽  
Sic Whiskers ◽  
Sic Composites

ZrB2/SiC ceramic composites reinforced by nano-SiC whiskers and SiC particles have been prepared by hot-pressing at 1950°C for 1hr under 20 MPa pressure in flow argon atmosphere. Effects of SiC addition on microstructure, mechanical properties and thermal ablation/oxidation behavior of ZrB2/SiC composites were investigated. The results showed that the addition of SiC effectively improved the densification of ZrB2/SiC composites and almost full dense ZrB2/SiC composites were obtained when the amount of SiC increased up to 20 vol%. Flexural strength and fracture toughness of the ZrB2/SiC composites were also enhanced; the maximum strength and toughness reached 600 MPa and 8.81 MPa·m1/2 at SiC additions of 20 vol % and 30 vol%, respectively. The composites possessed good resistance to flame ablation and could keep the whole shape without distinct peeling or cracking after flame ablation by oxyacetylene flame for 3 mins. The more SiC added, the better resistance to flame ablation the composites displayed.

Effect of Extrusion Parameters on Mechanical Properties of Al6061-Ni-P Coated SiC Composites

2013 ◽  
Author(s):  
Ramesh Chinnakurli Suryanarayana ◽  
Sikhakolli Ramakrishna ◽  
Ummar Khan Attaullah ◽  
Smitha Hanumantha Badnur ◽  
Kumar Saheb
Keyword(s):  
Mechanical Properties ◽  
Load Transfer ◽  
Hot Extrusion ◽  
Matrix Alloy ◽  
Extrusion Process ◽  
Systematic Investigation ◽  
Strength Properties ◽  
Industrial Applications ◽  
The Matrix ◽  
Sic Composites

Extrusion of metal matrix composites (MMCs) is a very challenging one where in the bond between the reinforcement and the matrix alloy is crucial in getting high quality extrusions for industrial applications. In recent years researchers are focusing on developing aluminium based composites with metallic coated reinforcement to achieve good interfacial bonds to ensure smooth load transfer from the matrix on to reinforcement. However no information is available as regards hot extrusion of metallic coated reinforced MMCs. In the light of the above, the present work focuses on a systematic investigation on effect of extrusion process parameters on mechanical properties of Al6061-Ni-P coated SiC composites. From the investigation, it is observed that hardness, yield and ultimate strength of Al2014-SiC (Both uncoated and Ni-P coated) composites are higher when compared with the matrix alloy for all the extrusion ratios studied (4:1,5:1,10:1,15.5:1) at a given extrusion temperature. However, the ductility of composites decreases with increase in extrusion ratios. Further, heat treatment has a significant effect on the studied mechanical properties. Increase in extrusion temperatures at a given extrusion ratio has resulted in decrease in hardness and strength properties of both matrix alloy and developed composites.

Mechanical properties of hot isostatically pressed Si3N4 and Si3N4/SiC composites

1993 ◽  
Vol 8 (3) ◽  
pp. 626-634 ◽  
Author(s):  
O. Unal ◽  
J.J. Petrovic ◽  
T.E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Hardness ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Sic Whiskers ◽  
Sic Composites ◽  
Increasing Temperature

The mechanical properties of hot isostatically pressed monolithic Si3N4 and Si3N4−20 vol. % SiC composites have been studied by microindentation at temperatures up to 1400 °C. Indentation crack patterns and microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. It is shown that dense Si3N4 base materials can be synthesized by HIPing without densification aids. Both the monolithic Si3N4 and the Si3N4/SiC composites exhibit high hardness values which gradually decrease with increasing temperature. Both types of material show low fracture toughness values apparently because of strong interfacial bonding. On the other hand, the fracture toughness of the composite is about 40% higher than that of the monolithic material, due to the presence of the 20 vol. % SiC whiskers. A crack deflection/debonding mechanism is likely to be responsible for the higher toughness observed in the composite. High resolution electron microscopy shows that the grain boundaries in both samples contain a thin SiO2 layer.

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