Tensile Fractography of Artificially Aged Al6061-SiC+B4C Hybrid Composites

2020 ◽  
Vol 995 ◽  
pp. 3-8
Author(s):  
Sathyashankara Sharma ◽  
M.C. Gowrishankar ◽  
Pavan Hiremath ◽  
Manjunath Shettar ◽  
B.M. Gurumurthy

In the current work Al6061 hybrid composites reinforced with Silicon Carbide (SiC) and Boron Carbide (B4C) were studied for improvement in hardness and behavior of fracture surface after artificial aging. It was found that after aging at 100 and 200 OC, presence of SiC and B4C particles in the Hybrid Al6061 Matrix Composites showed substantial improvement in hardness compared to that of the base alloy. Behavior of fracture mechanism after tensile strength have been discussed to conclude the factors which impact the mechanism of crack growth. Presence of SiC and B4C reinforcement particulates and artificially aged at 100°C for Al6061-SiC+ B4C hybrid metal matrix composite shows enhancement in hardness by 180% and tensile strength by 80% due to the presence of finer secondary solute rich intermetallic phases of alloying elements. Fractography analysis displays particle interface failure and combination of brittle and ductile mode of failure.

Author(s):  
Pawandeep Singh ◽  
RK Mishra ◽  
Balbir Singh

ZA-27 hybrid metal matrix composites reinforced with lamb bone ash (LBA) and boron carbide (B4C) were fabricated by employing stir casting route. Single-reinforced composite with 5 wt.% of LBA and hybrid composites reinforced with LBA/B4C in the ratio of (3.75:1.25, 2.5:2.5, 1.25:3.75) were developed. Composites were processed as per ASTM standards and subjected to physical characterization (density and porosity), microstructural characterization, and mechanical characterization (hardness, compressive strength, tensile strength, and impact strength). Microstructural studies of ZA-27 composites using a scanning electron microscope (SEM) revealed the uniform dispersion of reinforcements. X-ray diffraction (XRD) patterns and energy-dispersive X-ray spectroscopy (EDS) of the developed composites confirmed the existence of LBA and B4C particles in the matrix. The density of the composites declined, and porosity increased with the increment in B4C wt.% compared with base alloy. Mechanical properties like hardness, compressive strength, and tensile strength improved significantly in the case of hybrid composites than single-reinforced composite. Hardness, compressive strength and tensile strength of the hybrid composites increased to a maximum of 41.12%, 24.40%, 61.08% respectively compared to the base alloy, whereas single-reinforced composite showed maximum improvement of 19.26% (hardness), 11.16% (compressive strength), and 28.38% (tensile strength) compared to the base alloy. Ductility of the composites decreased with the addition of reinforcements. Impact strength of the composites showed a marginal reduction; however, the reduction was higher in the single-reinforced composite than hybrid reinforced composites. Fractured morphology showed dimples, cracks, tear ridges, and voids.


Author(s):  
Theerkka tharaisanan Rajamanickam ◽  
Kathiresan Marimuthu

Aluminium metal matrix composites (AMMC’s) have been widely used because of their superior properties like high strength to wear ratio, high wear resistance, and higher heat conduction rate. The additions of reinforcements in the form of discontinuous particles lead to an increase in the properties of Metal Matrix Composites (MMC). In this present work, the ALMMC composite was fabricated with the addition of discontinuous reinforcement particles of Zirconium Carbide (ZrC) and Boron Carbide (B4C). The mechanical properties such as tensile strength, hardness, and impact strength were tested as per the ASTM standards. The tribological properties were tested using a pin-on-disc setup under different loading conditions (10, 20, 30, 40 N). Moreover, the morphological characterization of ALMMC was carried out by using the Scanning Electron Microscope (SEM) analysis. Furthermore, the Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) was accomplished to find the thermal stability of ALMMC. The findings show that the variations of reinforcement of ZrC added had given improved properties like hardness, tensile strength, impact strength and wear resistance.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 193
Author(s):  
M.H. Faisal ◽  
S. Prabagaran ◽  
T.S. Vishnu

Aluminium/graphite composites are the need of modern times for addressing the fuel saving issues. The graphite in such composites act as solid lubricant and it reduce external fuel requirements. But such composites are having degraded mechanical properties due to the graphite content in composite. In order to solve the negative effect of graphite on mechanical properties of LM13/Gr self-lubricating composite this study was conducted to find out the mechanical properties of LM13/B4C/Gr Metal Matrix Composites. Boron carbide was selected as reinforcement because of its better reinforcement properties compared to alumina and silicon carbide. The properties of the hybrid composites were compared with the LM13/Gr self-lubricating composite to study the enhancement in mechanical properties that has been caused by the boron carbide particles. Using computerized universal testing machine and rock-well hardness tester mechanical properties such as hardness and tensile strength were tested. Pin on disk testing machine was used to analyse the wear behavior. The test results indicates that by raising weight % of boron carbide particles in the LM13, tensile strength and hardness of the hybrid composites was increased compared to self-lubricating composite accompanied by better tribological properties.


2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Kumaraswamy Jayappa ◽  
Vijaya Kumar ◽  
Gange Gowda Purushotham

Hybrid Metal Matrix Composites (HMMCs) have gained wide applications in aerospace, marine, and domestic areas because of its significant properties relative to external forces and enabling environment. In present research work, Ni-alloy selected as a matrix and Al2O3 of 40–80 μm and TiO2 of 1–5 μm were selected as reinforcements. The composites were prepared by keeping 9 wt. % of TiO2 as unvarying and Al2O3 is varied from 3 weight % to 12 weight % in steps of 3 weight %. Induction furnace is used for the casting of composites and mixing is done by using mechanical stirring at 160 rpm for a time period of 5 min. The prepared composites are then tested for their tensile and hardness as per the ASTM standards. The Scanning Electron Microscopy was used for microstructural study. From experimentation, it was observed that increment in the weight percentage of Al2O3 with constant TiO2 increases the mechanical properties of hybrid composites and proper stirring improves homogeneity in the composite material. The test results show that the addition of Al2O3 up to 9 weight percent increases in tensile strength compared to Ni alloy and tensile strength slowly decreases with the addition of Al2O3 and that the hardness values are directly proportional to the weight percent of the addition of Al2O3 / TiO2.


Hybrid composites are those composites which have a combination of two or more reinforcements in a single matrix. In this study, Hybrid Aluminum Metal Matrix Composites were fabricated by using Stir Casting technique. Hybrid composites with three reinforcements such as Aluminum oxide(Al2O3 ), Silicon Carbide (SiC) and Boron Carbide (B4C) in different proportions are considered and Aluminum alloy 6061-T6 (Al6061) as base alloy matrix. Later, the cast aluminum metal matrix composites were machined as per ASTM standards with required dimensions. Mechanical tests such as tensile, flexural, Charpy impact, Brinell Hardness tests were conducted on the composites fabricated inorder to evaluate effect of reinforcements. Morphological study of the composites is carried out by using Scanning electron microscope (SEM). The test results were studied and analyzed.


Author(s):  
S. Iyengar ◽  
D. Sethuram ◽  
R. Shobha ◽  
P.G. Koppad

T1B2 and CeO2 particle-reinforced A16061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500°C and a 50% reduction was achieved through 12 passes. The effect of varying TB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites.


Author(s):  
Shashank Dewangan ◽  
S. K. Ganguly ◽  
R. Banchhor

Aluminium Hybrid Composites are the new group of metal matrix composites (MMCs) due to their attractive properties like high ductility, high conductivity, light weight and high strength to weight ratio and is a response to the dynamic ever-increasing demand of these super material in the field of aircrafts and marines. Carbon Nanotube (CNTs) are also known for their high strength and stiffness and their low density which when combined together makes CNTs an ideal reinforcement. This work briefly reviews the research revelation of an Aluminium (Al-6061) based hybrid metal matrix composite reinforced with CNTs and TiO2. The Hybrid Aluminium Metal Matrix Composites (AMMCs) is prepared with various CNTs weight percentages (0, 0.5, 1 and 1.5 wt. %) and keeping TiO2 weight percentage fixed to 1%.Stir Casting (SC) is focused in general to successfully fabricate the MMCs. The discussion of this work revolves around tensile test, hardness test, and Scanning Electron Microscope (SEM) of the MMC. The mechanical properties of the fabricated MMCs materials like tensile strength, hardness and impact strength is found by using these experimental methods. It has been observed that the tensile strength of the MMCs increases in the presence of TiO2 and CNTs and increases even more with the increase in the weight fraction of CNTs. Same results have been obtained for hardness and impact strength where there is an increase in them in the presence of TiO2 and CNT and their value increases even further with increase in weight fraction of CNTs.


2014 ◽  
Vol 592-594 ◽  
pp. 705-710 ◽  
Author(s):  
S. Dhanalakshmi ◽  
N Mohanasundararaju ◽  
P.G. Venkatakrishnan

A hybrid Al7075 metal matrix composites have been fabricated through liquid metallurgy route (Stir Casting method) using Al2O3 and B4C as reinforcement materials. The effect of weight percentage of reinforcement materials on mechanical properties of the composites have been studied by varying the weight percentage of Al2O3 as 3, 6, 9, 12 and 15% while keeping constant weight percentage of B4C (3%). The as-cast microstructure, tensile strength, micro and macro hardness of the fabricated hybrid composites have been studied. The mechanical properties of the prepared composites were increased with increasing the weight percentage of the reinforcement in the composite. The maximum tensile strength, micro-hardness and macro-hardness of 309 MPa, 140 VHN, and 112 BHN, respectively, were obtained for a hybrid Al7075 matrix composite containing 15% Al2O3 and 3% B4C.


2020 ◽  
Vol 979 ◽  
pp. 34-39
Author(s):  
K. Sudhindra Srinivas ◽  
M. Murali Mohan

The epidemic adoption of particulate metal matrix composites (MMCs) for engineering applications has been delay by the high cost of producing components of even minimally complex shape. The aluminum-based composites find its applications widely in transport, aerospace, marine, automobile and mineral processing industries, owing to their improved strength, stiffness and wear resistance properties. This paper, presents the overview of the addition of different reinforcements to aluminium alloy. The reinforcements are added to the Al7075 by using stir casting method. Effect of these reinforcements like Titanium carbide (TiC) and silicon (Si) influencing on the mechanical properties like tensile strength, hardness was studied. Research relevant to these factors which influence particles distribution were noticed by conducting the experimental studies of Al7075 hybrid composites.The mechanical properties and the microstructure of Al–TiC-Si metal matrix composite has shown the significant improvement in Hardness and Tensile strength, with increase in TiC and Si particles in weight percentage of composites.


2017 ◽  
Vol 263 ◽  
pp. 184-188 ◽  
Author(s):  
P. Subramanya Reddy ◽  
R. Kesavan ◽  
B. Vijaya Ramnath

The investigation of mechanical properties of silicon carbide (SiC) powders reinforced with aluminum alloy composites are recorded in this paper. SiC powders of approximately 35µm size were added in an aluminum alloy matrix to manufacture the samples of ratios 1, 2, 3 and 4 by weight % using the stir casting technique. The specimens were fabricated and several tests were conducted to evaluate the mechanical properties such as tensile strength, hardness and impact strength and then the values are compared with the base alloy. It has been observed from the results that the hardness, impact energy and tensile strength increases with the increase in % of SiC particles until 2% and drops on further increase in the SiC particles.


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