On the Mechanical Properties and Fracture Behavior of Zr and Ti-Containing Al-15vol% B4C Based Metal Matrix Composites (original) (raw)
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On the impact toughness of Al-15 vol. % B4C metal matrix composites
Composites Part B: Engineering, 2015
The present work was performed on ten metal matrix composites (MMCs) produced using the new powder injection technique. These MMCs were divided into two series in which pure aluminum was the matrix for one series, while an experimental 6063 alloy was the matrix for the second series. Small amounts of Ti, Zr and Sc were added to those composites, either individually or combined. In all cases the volume fraction of the reinforced B 4 C particles was in the range 12e15 vol. %. The molten metal was cast in an L-shaped metallic mold preheated at 350 C. Unnotched rectangular impact samples (1 cm  1 cm  5 cm) were prepared from these castings and heat treated. Samples were tested using instrumental impact testing machine. Microstructure and fracture surface were examined using Hitachi SU-8000 FESEM. The results show that the presence of Ti improves the wettability of the B 4 C particles and their adherence to the matrix. Repeated remelting at 730 C applying vigorous mechanical stirring could lead to fragmentation of some of the B 4 C particles. Aluminum based composites exhibited better toughness compared to those obtained from 6063 based composites in all the studied conditions. The composite impact toughness was controlled by the precipitation and coarsening of hardening phase particles namely Mg 2 Si, Al 3 Zr and/or Al 3 Sc. Cracks in the fracture surface were observed to be initiated at the particle/matrix interfaces and propagate either through the B 4 C particles or through the protective layers. No complete debonding was reported due the presence of Zr/Ti/Sc rich layers which improved the particle/matrix adhesion.
IRJET, 2022
Aluminum matrix composite is a new generation of metal matrix composite which have the tendency to meet the emerging for advanced engineering application. The performance of these materials mostly depends upon selecting right combinations of reinforcing materials. In the current work an effort as been made for the fabrication of Aluminum metal matrix composite for the investigation of its mechanical properties. The preparation of aluminum metal matrix composite is made by choosing AA6082 as matrix and by keeping weight % of reinforcements ZrO2 and the Ti are varied by 2%, 4% and 6%. The wear properties of metal matrix composites were studied by conducting wear test using pin on disc machine as per ASTM G-99 standard. The experiment were conducting by adopting the taquchi technique with an L9 orthogonal array and analysis of variance approach was employed to evaluate the effect wear parameters load, percentage reinforcement and duration on wear rate of composites. These samples were fabricated by means of stir casting technique and the micro structural characteristics of composites are studied by using optical microscope. Mechanical properties such as impact strength, hardness, compression are studied and compared the results with base Aluminum 6082 results.
Al Matrix Composites Reinforced by Ti and C Dedicated to Work at Elevated Temperature
2021
In this paper, the applicability of aluminium matrix composites to high-temperature working conditions (not exceeding the Al melting point) was evaluated. The behaviour of Al-Ti-C composites at elevated temperatures was described based on microstructural and phase composition observations for composites heated at temperatures of 540 and 600 °C over differing time intervals from 2 to 72 h. The materials investigated were aluminium matrix composites (AMC) reinforced with a spatial carbon (C) structure covered by a titanium (Ti) layer. This layer protected the carbon surface against contact with the aluminium during processing, protection which was maintained for the material’s lifetime and ensured the required phase compositions of Al4C3 phase limitation and AlTi3 phase creation. It was also proved that heat treatment influenced not only phase compositions but also the microstructure of the material, and, as a consequence, the properties of the composite.
" Fatigue and Fracture Toughness Behavior of Al 2219/B 4 C Particulate Metal Matrix Composites "
In the present study, the fatigue and fracture toughness behavior of Al 2219/B 4 C particulate metal matrix composites is investigated. The composites were fabricated by reinforcing B 4 C particles of 125microns with varying wt% of 2 and 4, using stir casting process. The performance of the prepared composites was compared with the alloy Al 2219 to study the improvement in fatigue and fracture toughness behavior as a result of reinforcement particles. The homogeneous dispersion of the reinforcement particles in the matrix was examined using optical microscope. The result reveals that the addition of B 4 C improves both fatigue strength and fracture toughness of composites over the alloy, further by increasing the wt% of B 4 C reinforcement in the matrix, there was a significant improvement in both the properties. As load increases there was decreasing cycles which indicates load has more effect on the fatigue strength. Overall, fatigue strength and Fracture toughness of the composites was improved to 63.97% and 33.34% respectively with respect to 4wt% B4C particles reinforcement compare to base alloy.
Precipitation phenomena in Al-Zn-Mg alloy matrix composites reinforced with B4C particles
Scientific Reports
To provide insight into precipitation phenomena in age-hardening Al-Zn-Mg(-Cu) matrix composites, an Al 7075 alloy composite reinforced with B 4 C particles was selected as a model system. The bulk composites were fabricated via plasma activated sintering and followed by a peak aged (T6) heat treatment. Two types of Al matrix zones were identified in the composite: (1) the regions in the vicinity of the matrix/reinforcement interface, defined as "matrix plastic zone" (MPZ) hereafter, and (2) the regions away from the matrix/reinforcement interface, simply defined as matrix hereafter. The precipitation behavior in the MPZ was characterized and compared to that in the matrix. The MPZ contained a high density of dislocations. The number density of GP zones in the MPZ is lower than that in the matrix while the average size of the GP zones in MPZ is coarser. In addition, semi-coherent platelet η′ precipitates were observed but only in the MPZ. The dislocations and the Al/B 4 C interfaces provide more heterogeneous nucleation sites for the η′ precipitates in the MPZ. The growth and coarsening of the η′ precipitates caused rapid depletion of Mg and Zn solute atoms in the MPZ. Al-based metal matrix composites (MMCs) containing ceramic particle reinforcements are of interest partly due to the fact that they can be processed using flexible approaches, including: powder metallurgy, preformed infiltration as well as a variety of casting technologies 1-3. Review of the published literature shows that interest in precipitation hardened, Al-based MMCs stems from their technological potential, as well as from the underlying scientific questions associated with these materials 4-7. On one hand, an age-hardened Al alloy matrix has the potential to further increase the strength of the composite beyond the strengthening contribution from the reinforcement phase; on the other hand, the aging kinetics in the matrix alloy are influenced by the presence of the reinforcement particles which leads to interesting questions 5, 6, 8-11. For example, how are aging kinetics influenced by the characteristics of the reinforcement particles (i.e., chemistry, size and distribution), the processing method, and the heat treatment conditions 12, 13 ? Amongst age-hardening Al alloys, Al-Zn-Mg(-Cu) alloys have been the subject of extensive research in the past decades due to their inherent high strength and stiffness 8. The precipitation behavior in this alloy family is rather complicated, especially during the early stages, because of its sensitivity to the local chemical composition of the alloys and the heat treatment environment. Nevertheless, it is generally accepted that the precipitation sequence is the same for most of the Al-Zn-Mg alloys, and can be summarized as follows 14-18 : Supersaturated solid solution (SSS) → Guinier-Preston zone (GP zone, coherent Mg and Zn-rich clusters) → η′ (semi-coherent MgZn 1−2) → equilibrium η (incoherent MgZn 2 , hexagonal structure). Some studies hypothesized that the precipitation sequence in the unreinforced matrix and that in the corresponding composites are identical 5, 19. As a result, in an effort to promote precipitation, composites with age-hardening Al alloy matrix are usually given identical heat treatments as those used for the corresponding age-hardening Al alloys, including solution treatment, quenching, and aging. Interestingly, one critical factor that affects precipitation behavior is the role of dislocations, which has been neglected in most studies. Despite the fact that most of the dislocations are annihilated when the materials are heated during solution heat treatment,
Aluminium materials have a massive demand in the fields of automotive, aerospace and different engineering applications in order to meet requirements of various fields. A material with sound mechanical and thermal properties is produced which is metal matrix composites in which aluminium alloy is used as a common matrix phase and different material particulates and fibers are used as a reinforcement. Experimental MMC components are being developed and find their applications in aircraft, satellites, jet engines, missiles, and space shuttle industries. In this study, ceramic materials are used as reinforcements for MMCs such as Sic, Al 2 O 3 , B4c and TiB 2. Al7075 is used as a base matrix material. Metal matrix composites can be fabricated using different ceramic reinforcements and in this work, stir casting method, which is a liquid metallurgy technique, is used to produce the composite materials. Four different MMCs are produced with 15% Sic, 15% Al 2 O 3 , 15% B4c, and 15% TiB 2. The Mechanical Characteristics such as hardness, tensile strength, and impact strength are studied for these composites. The obtained results were compared and graphically charted to characterize these materials.
Journal of Materials Research, 1993
The effect of solid state heat treatment at 913 K on extruded XD Al/TiC metal matrix composite with 0.7 and 4.0 /nm particle sizes has been investigated. The interfaces between Al and TiC after extrusion were atomically abrupt, as observed by HRTEM. On holding at 913 K, the composite with submicron particle size showed substantial changes in the phases present due to reaction between Al and TiC at 913 K. The stable reaction products are Al 3 Ti and A1 4 C 3 . A substantial increase in Young's modulus occurs. The room and elevated temperature strength and hardness of the composite with submicron particles also increase significantly with time of heat treatment, but at the expense of ductility. The effect of heat treatment over the time range investigated is limited to the interfaces for the 4.0 /xm TiC particle size composite due to longer diffusion paths.
On the Impact Toughness of Al-B4C MMC: The Role of Minor Additives and Heat Treatment
Two base alloys of Al-15 vol.% B4C and 6063-15 vol.% B4C metal matrix composites (MMCs) were produced using a powder injection technique. Alloying additions of 0.5wt.% Ti, 0.35wt.% Zr and 0.35wt.% Sc were made to the base alloys to produce various compositions of the two MMCs. For the purpose of investigating the effect of reinforcement/matrix (B4C/Al) interaction on the composite toughness, ten compositions of pure Al-15 vol.% B4C and 6063-15 vol.% B4C with various additions of Ti, Zr and Sc were produced. A metallic L-shaped mould was used for casting the aluminum MMCs. Reinforcement/matrix interface interactions in the produced composites were investigated as a function of the alloying elements added using field emission gun scanning electron microscopy (FEGSEM) and energy dispersive x-ray (EDX) techniques. The results show that the toughness of a given composite is controlled by the type of heat treatment and amount of added elements or refractory materials. Introduction of Ti alone leads to reaction with some of the B4C particles, converting them to Al-Ti-B or Al-Ti-C compounds. The addition of Zr reacts with Ti forming Al3(Ti,Zr) which minimizes the particle/matrix interaction. Repeated remelting of the composite coupled with a high stirring speed may cause fragmentation of the B4C particles.
Recent developments in material technology help to find and fabricate new materials which may replace existing materials for various applications. Among those, composite materials play a vital role which is combination of two or more materials with different physical and chemical properties. Aluminum plays a vital role in the automotive, aerospace and marine industries this for its strength, less weight, flexibility and cost. The present study is to cast a metal matrix composite of al 6061 with the selected reinforcing materials. The reinforcing material used here are titanium (Ti), tungsten carbide (Wc), boron carbide (B 4 C) and chromium (Cr) in the form of particles. The casting is done using the stir casting method and the mechanical properties and SEM analysis of the hybrid composites are tested with the ASTM standard's and are compared with the pure Al6061. The mechanical properties of the aluminum metal matrix composites such as impact, tensile and hardness are tested. The tensile specimens hardened using the annealing and normalizing process and the tests are taken with the different specimens and these are compared with Al6061. Heat treatment effect on mechanical properties and SEM analysis of Al6061/Wc/B 4 C/Ti/Cr metal matrix composites
High Temperature Mechanical Properties and Wear Performance of B4C/Al7075 Metal Matrix Composites
Metals, 2019
In this study, high volume fraction B4C reinforced Al matrix composites were fabricated with a liquid pressing process. Microstructural analysis by scanning electron microscope and a transmission electron microscopy shows a uniform distribution of the B4C reinforcement in the matrix, without any defects such as pore and unwanted reaction products. The compressive strength and wear properties of the Al7075 matrix and the composite were compared at room temperature, 100, 200, and 300 °C, respectively. The B4C reinforced composite showed a very high ultimate compression strength (UCS) over 1.4 GPa at room temperature. The UCS gradually decreased as the temperature was increased, and the UCS of the composite at 300 °C was about one third of the UCS of the composite at room temperature. The fractography of the compressive test specimen revealed that the fracture mechanism of the composites was the brittle fracture mode at room temperature during the compression test. However, at the elev...