Research on Fabrication and Semisolid Processing of Semisolid Slurries of 7075 Aluminum Matrix Composites Reinforced with Nano-Sized SiC Particles

2016 ◽  
Vol 256 ◽  
pp. 81-87 ◽  
Author(s):  
Ju Fu Jiang ◽  
Ying Wang ◽  
Shou Jing Luo

Semisolid slurries of 7075 aluminum matrix composite reinforced with nano-sized SiC particles were fabricated by ultrasonic assisted semisolid stirring (UASS) method. Rheoforming and thixoforming of typical cylindrical parts were investigated. The results show that high-quality semisolid slurries with spheroidal solid grain of 38 µm were fabricated by UASS. The nano-sized SiC particles were dispersed uniformly due to transient cavitation and acoustic streaming of ultrasonic wave and high and controllable viscosity of semisolid slurry. Typical cylindrical composite parts with good surface quality and complete filling were rheoformed and thixoformed successfully. Ultimate tensile strength (UTS) of the rheoformed and thixoformed composite parts are enhanced due to addition of nano-sized SiC particles. However, elongation decreased as compared to those of the matrix parts. Maximum UTS of 550 MPa was achieved in the thixoformed composite part with T6 treatment. Increase of dislocation density around the reinforcement particles leads to improvement of the strength and wear resistance of the composite.

2017 ◽  
Vol 52 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Mohammad Senemar ◽  
Behzad Niroumand ◽  
Ali Maleki ◽  
Pradeep K Rohatgi

In this study, in situ aluminum matrix composites were synthesized through pyrolysis of high temperature vulcanization silicone in commercially pure aluminum melt. For this purpose, 1 to 4 wt% of high temperature vulcanization silicone was added to a vortex of molten aluminum at 750℃ and the resulting slurries were cast in steel dies. Microstructure, hardness, and tensile properties of the as-cast samples were examined at ambient and high temperatures. The results revealed the in situ formation and distribution of reinforcement particles in the matrix. Energy-dispersive X-ray analysis indicated that the formed reinforcement particles consisted of O and Si elements. This confirms the in situ reinforcement formation by pyrolysis of high temperature vulcanization silicone in the melt. The size of the in situ formed particles was mostly in the range of 200–2000 nm. It was shown that the composites synthesized by the addition of 4 wt% high temperature vulcanization had the highest mechanical properties both at ambient and high temperatures. Room temperature hardness, tensile strength, and yield strength of this sample were increased by about 50%, 23%, and 19% compared to the monolithic sample, respectively.


2017 ◽  
Vol 898 ◽  
pp. 917-932 ◽  
Author(s):  
Yong Wang ◽  
Ji Xue Zhou ◽  
Kai Ming Cheng ◽  
Jian Hua Wu ◽  
Yuan Sheng Yang

Graphene with unique two-dimensional structure and excellent mechanical properties, is one of the most ideal reinforcements. With the increasing progress of aluminum matrix composites, graphene reinforced aluminum matrix composites have attracted great interests. This paper mainly reviews the latest progress on preparation of graphene reinforced aluminum matrix composites, and especially discusses the effective dispersion technique of graphene. Meanwhile, the microstructure and interfacial structure of graphene reinforced aluminum matrix composites are also emphasized and discussed. The results showed that graphene can significantly improve the mechanical properties of composites and refine the matrix grain. By controlling preparation parameters, the graphene agglomeration can be effectively solved, and the adverse interface reaction between graphene and substrate can be avoided. Finally, the current challenges and solutions of graphene reinforced aluminum matrix composites were presented.


2020 ◽  
Vol 988 ◽  
pp. 17-22
Author(s):  
Suryana ◽  
Indah Uswatun Hasanah ◽  
Muhammad Fikri Fadhillah ◽  
Yordan Valentino Putra

The effects of graphite and magnesium (Mg) addition on mechanical properties and microstructure of aluminum matrix composites (AMCs) have been investigated in this work. Aluminum alloy (ADC-12) was combined with graphite and Mg produced by stir casting. The effect of addition of graphite into the matrix has been studied with variation 2, 4 and 6 wt-% for each composite. The addition of Mg as wetting agent was introduced wit 0.4, 0.6 and 0.8 wt-% to promote wettability between ADC-12 and graphite. All composites were characterized both microstructures analysis and mechanical properties include tensile strength and hardness. The higher reinforcement content, the higher porosity formed, due to the tendency of de-wetting as well as particles agglomeration. One of the main intermetallic phase present evenly in aluminum matrix is Mg2Si. The addition of magnesium in the material that will form Mg2Si primary phases which have a high hardness value of these composites.


1994 ◽  
Vol 372 ◽  
Author(s):  
M. T. Kiser ◽  
M. He ◽  
B. Wuj ◽  
F. W. Zok

AbstractThe compressive deformation characteristics of hollow alumina microsphere reinforced aluminum matrix composites have been studied through both experiments and finite element analysis of unit cell models. Tests have been performed on composites containing around 50 volume percent of microspheres. The effects of the matrix flow stress and microsphere morphology (characterized by the ratio of wall thickness to radius) have been examined. The measured strength enhancement due to the hollow microspheres was found to be considerably less than that predicted by the FEM calculations; a result of microsphere cracking. Experiments have been conducted to document the progression of such damage following casting and mechanical deformation. The potential of this class of composite for impact energy absorption applications is also explored.


2014 ◽  
Vol 21 (1) ◽  
pp. 29-38
Author(s):  
Oscar Marcelo Suárez ◽  
Natalia Cortes-Urrego ◽  
Sujeily Soto-Medina ◽  
Deborah Marty-Flores

AbstractAn aluminum-copper matrix composite reinforced with aluminum diboride particles was studied at high temperature via thermomechanometry experiments. The matrix contained 2 wt% Cu, whereas the amount of boron forming AlB2 ranged from 0 to 4 wt%, i.e., 0 to 8.31 vol% of diboride particles. In the first segment of the research, we demonstrated that larger amounts of AlB2 particles raised the composite hardness even at 300°C. To assess the material creep behavior, another set of specimens were tested under 1 N compression at 400°C and 500°C for 12 h. Higher levels of AlB2 allowed the composites to withstand compression creep deformations at those temperatures. By using existing creep models developed for metal matrix composites we were able to determine that viscous slip deformation was the dominant deformation mechanism for the temperatures and stress levels used in our experiments. Additionally, the computed creep activation energy for these aluminum matrix composites were found comparable to the energies reported for other similar materials, for instance, Al/SiCp composites.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 44 ◽  
Author(s):  
Peng-Xiang Zhang ◽  
Hong Yan ◽  
Wei Liu ◽  
Xiu-Liang Zou ◽  
Bin-Bing Tang

In this study, 7075 aluminum matrix composites reinforced with 1.5 wt.% nanosized Al2O3 were fabricated by ultrasonic vibration. The effect of T6 heat treatment on both microstructure and hardness of nanosized Al2O3 reinforced 7075 (Al2O3np/7075) composites were studied via scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, transmission electron microscopy, and hardness tests. The Mg(Zn,Cu,Al)2 phases gradually dissolved into the matrix under solution treatment at 480 °C for 5 h. However, the morphology and size of Al7Cu2Fe phases remained unchanged due to their high melting points. Furthermore, the slenderness strips MgZn2 phases precipitated under aging treatment at 120 °C for 24 h. Compared to as-cast composites, the hardness of the sample under T6 heat treatment was increased ~52%. The strengthening mechanisms underlying the achieved hardness of composites are revealed.


2008 ◽  
Vol 41-42 ◽  
pp. 61-67
Author(s):  
Li Liang ◽  
Ming Li ◽  
Chi Tay Tsai

Dynamic properties of Nanostructured Metal Matrix Composites (NMMCs) materials consisting of nanograined aluminum matrix with nano or micro-sized ceramics particulates are calculated using Ansys/LS-DYNA in this paper. There are three conditions for the mechanics analysis involved the target with 10 vol. % SiC, 30 vol. % SiC and 50 vol. % SiC. It is assumed that the SiC particles uniformly distributed in the matrix. According to the analysis, the strength of NMMCs material is reduced, and the deformation of target is weakened by the vol. % of SiC increasing.


2020 ◽  
Author(s):  
Zheng-Hua Guo ◽  
Qingjie Wu ◽  
Ning Li ◽  
Li-Hong Jiang ◽  
Wen He ◽  
...  

Abstract Graphene nanoplatelets (GNPs) reinforced 7075 aluminum (Al) nanocomposites were successfully synthesized using the powder metallurgy method. A novel method for optimizing interfacial bonding by coating titanium dioxide (TiO 2 ) on the surface of GNPs was proposed in this manuscript. The effects of GNPs on mechanical properties and microstructure of the aluminum matrix nanocomposites, both with and without TiO 2 coating layers, have been investigated. Experimental results showed that the corresponding mechanical properties of the nanocomposites were further improved when the GNPs have TiO 2 coating layers, compared with the addition of pure GNPs. The yield strength, ultimate tensile strength, and microhardness of the nanocomposites reinforced with TiO 2 -coated GNPs increased by 22.9%, 25.9%, and 20.1%, respectively, in comparison to those of the matrix. The further improvement of the mechanical properties could be attributed to the existence of the coating layer, which optimizes the interface bonding between the reinforcement and the matrix, thereby improving the effectiveness of load transfer.


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