Damping and Mechanical Properties of (Graphite + 9Al2O3·2B2O3)/Mg Metal Matrix Composites

2004 ◽  
Vol 449-452 ◽  
pp. 657-660
Author(s):  
Il Dong Choi ◽  
Dong Min Kim ◽  
Kyung Mok Cho ◽  
Ik Min Park

Mg alloys have potential to use automotive parts because of their weight and castability. High temperature strength and damping capacity is important to the automotive power train parts. Mg alloy has lower creep and thermal fatique strength but has better damping capacity than Al alloy. It is known that short fiber reinforced Mg metal matrix composites(MMC) exhibits superior high temperature strength and graphite reinforced Mg MMC shows excellent damping capacity. Therefore, in this study, the effect of graphite particles(15-25%) and alborex (9Al2O3ּ2B2O3) whiskers(5-15%) on the damping behavior and mechanical properties of Mg MMC was studied. Graphite particles and alborex whiskers were chosen to increase damping capacity and high temperature strength, respectively. The Mg MMC was fabricated by squeeze casting and the total quantity of reinforcements(graphite + alborex) was maintained to 30 volume percent. The damping capacity of the metal matrix composites was increased and the flexural strength and hardness were decreased with increasing the volume fraction of graphite particles, that is, reducing the volume fraction of alborex whiskers.

2015 ◽  
Vol 813-814 ◽  
pp. 116-120
Author(s):  
K.S. Arun ◽  
T. Panneerselvam ◽  
S. Raghuraman

Now a day’s Hybrid Metal Matrix composites has a large number of applications in automobiles, aircrafts and structural applications like brake rotors, engine parts and cylinder liners. The aim of this study is to determine the mechanical properties of boron carbide (B4C) and zirconium silicate (ZrSiO4) particulate reinforced with AA6063 alloy composites. In this experimental study, B4C and ZrSiO4 particulates reinforced with AA6063 composites were manufactured by stir casting technique. Mechanical properties of these composite materials were investigated by different weight percentages, 3%, 6%, 9% of boron carbide (B4C) and 9%, 6%, 3% of zirconium silicate (ZrSiO4) respectively. The mechanical properties evaluation reveals variations in hardness and the tensile strength values with the composite combinations investigated in this work. From the experimental studies, the optimum volume fraction of hybrid reinforcement in AA6063 alloy on the basis of mechanical properties and SEM analysis is also determined.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1588
Author(s):  
Seongmin Ko ◽  
Hyeonjae Park ◽  
Yeong-Hwan Lee ◽  
Sangmin Shin ◽  
Ilguk Jo ◽  
...  

This study was conducted on titanium diboride (TiB2) reinforced Al metal matrix composites (MMCs) with improved properties using a TiB2 and aluminum (Al) 1050 alloy. Al composites reinforced with fine TiB2 at volume ratios of more than 60% were successfully fabricated via the liquid pressing infiltration (LPI) process, which can be used to apply gas pressure at a high temperature. The microstructure of the TiB2–Al composite fabricated at 1000 °C with pressurization of 10 bar for 1 h showed that molten Al effectively infiltrated into the high volume-fraction TiB2 preform due to the improved wettability and external gas pressurization. In addition, the interface of TiB2 and Al not only had no cracks or pores but also had no brittle intermetallic compounds. In conclusion, TiB2–Al composite, which has a sound microstructure without defects, has improved mechanical properties, such as hardness and strength, due to effective load transfer from the Al matrix to the fine TiB2 reinforcement.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3947
Author(s):  
Myung Eun Suk

By using the advantages of carbon nanotubes (CNTs), such as their excellent mechanical properties and low density, CNT-reinforced metal matrix composites (MMCs) are expected to overcome the limitations of conventional metal materials, i.e., their high density and low ductility. To understand the behavior of composite materials, it is necessary to observe the behavior at the molecular level and to understand the effect of various factors, such as the radius and content of CNTs. Therefore, in this study, the effect of the CNT radius and content on the mechanical properties of CNT-Al composites was observed using a series of molecular dynamics simulations, particularly focusing on MMCs with a high CNT content and large CNT diameter. The mechanical properties, such as the strength and stiffness, were increased with an increasing CNT radius. As the CNT content increased, the strength and stiffness increased; however, the fracture strain was not affected. The behavior of double-walled carbon nanotubes (DWNTs) and single-walled carbon nanotubes (SWNTs) was compared through the decomposition of the stress–strain curve and observations of the atomic stress field. The fracture strain increased significantly for SWNT-Al as the tensile force was applied in the axial direction of the armchair CNTs. In the case of DWNTs, an early failure was initiated at the inner CNTs. In addition, the change in the elastic modulus according to the CNT content was predicted using the modified rule of mixture. This study is expected to be useful for the design and development of high-performance MMCs reinforced by CNTs.


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