scholarly journals Manufacturing of Light Metal Matrix Composites by Combined Thermal Spray and Semisolid Forming Process – Summary of the Current State of Technology

2010 ◽  
Vol 425 ◽  
pp. 217-244 ◽  
Author(s):  
Martin Wenzelburger ◽  
Martin Silber ◽  
Rainer Gadow
Keyword(s):  
Aluminum Matrix ◽  
Matrix Alloy ◽  
Aluminum Matrix Composites ◽  
Coating Process ◽  
Matrix Composites ◽  
Short Fibers ◽  
Cycle Times ◽  
Fiber Damage ◽  
Semisolid Forming ◽  
The Matrix

The demand for lightweight structures in the automotive and aerospace industry increases permanently, and the importance of lightweight design principles is also increasing in other industrial branches, aiming towards improved energy efficiency and sustainability. Light metals are promising candidates to realize security relevant lightweight components because of their high specific strength; and amongst them, aluminum alloys are the most interesting materials due to their high plasticity and strain to failure, good processability, passivation in oxygen containing atmosphere, and low cost. However, for many applications, their stiffness as well as strength and fatigue behavior at elevated temperature are insufficient. Metal matrix composite (MMC) formation by integration of reinforcements in the form of continuous or discontinuous (short) fibers can yield a high increase in the alloys’ specific mechanical properties at room temperature and at elevated temperature. The integration of fibers with conventional manufacturing techniques like squeeze casting, hot pressing or diffusion bonding leads to restrictions in the component’s geometry. Moreover, these techniques result in elevated process costs mainly caused by long cycle times and the need of additional protective fiber coatings. In the present paper, an alternative method for the manufacturing of aluminum matrix composites is described, combining thermal spraying and semisolid forming (thixoforging) technologies for the formation of fiber prepregs and subsequent forming with simultaneous densification. Therefore, prepregs with the matrix alloy as a thick surface coating on the reinforcement fibers are manufactured in a fast, automated coating process, while reheating, densification and shaping are performed in a separate process, allowing an optimization of both processes towards cycle times and resulting material properties. Continuous fiber and short fiber reinforced aluminum matrix composites are manufactured using woven or parallel arranged continuous fibers, or short fibers as a fleece or fiber paper material. For the coating process, twin-wire electric arc spraying is applied as a well established, cost efficient thermal spray technology. The coating process is optimized towards microstructure of the matrix alloy prior to semisolid forming, which requires a globular alloy microstructure, and reduced fiber damage during the high-temperature liquid melt deposition. The thermally sprayed fine-grained matrix material enables semisolid forming at liquid contents of 40-60 vol% of the alloy, with short flow paths, reduced mechanical loads and short cycle times. Thus, limited fiber damage and residual stresses will occur, leading to good mechanical material properties. A production line for industrial-scale coating of fiber fabric coils in a continuous process is introduced in order to provide prepregs of various fiber-reinforcement materials and fiber architectures; moreover, a winding equipment for simultaneous fiber winding and coating is presented that enables local reinforcement for components with adapted, tailored composite material design.

Effects of Particle Size on Microstructure of the Matrix Alloy in Aluminum Matrix Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1655-1659
Author(s):  
Long Tao Jiang ◽  
Gao Hui Wu ◽  
Min Zhao ◽  
Qiang Zhang ◽  
Norio Kouno ◽  
...  
Keyword(s):  
Squeeze Casting ◽  
Aluminum Matrix ◽  
Matrix Alloy ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Casting Technique ◽  
Al Composite ◽  
The Matrix ◽  
Mismatch Stress ◽  
Thermal Mismatch Stress

Aluminum matrix composites, reinforced by 0.15μm and 5μm Al2O3 particles with 40% volume fractions were fabricated by squeeze casting technique. The microstructure characterization near the interfaces of Al2O3p/1070Al composites was investigated by SADP and HREM techniques. Results showed that high-density dislocations were generated in the 5μm-Al2O3p/Al composite due to the thermal mismatch stress. In contrast, the matrix of the 0.15μm-Al2O3p/Al composite appeared to be nearly free dislocations and some “micro distortion areas” of 1-5nm were observed, which was attributed to the dispersion of fine sub-micron particles and uniform distribution of the stress near the interfaces.

Compressive Deformation of Hollow Microsphere Reinforced Metal Matrix Composites

1994 ◽  
Vol 372 ◽  
Author(s):  
M. T. Kiser ◽  
M. He ◽  
B. Wuj ◽  
F. W. Zok
Keyword(s):  
Aluminum Matrix ◽  
Hollow Microsphere ◽  
Compressive Deformation ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Element Analysis ◽  
Strength Enhancement ◽  
The Matrix ◽  
Matrix Flow ◽  
Measured Strength

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.

High-temperature mechanical behavior of Al-Cu matrix composites containing diboride particles

2014 ◽  
Vol 21 (1) ◽  
pp. 29-38
Author(s):  
Oscar Marcelo Suárez ◽  
Natalia Cortes-Urrego ◽  
Sujeily Soto-Medina ◽  
Deborah Marty-Flores
Keyword(s):  
High Temperature ◽  
Aluminum Matrix ◽  
Copper Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Compression Creep ◽  
The Matrix ◽  
Material Creep ◽  
Copper Matrix Composite ◽  
Composite Hardness

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.

scholarly journals Effect of T6 Heat Treatment on Microstructure and Hardness of Nanosized Al2O3 Reinforced 7075 Aluminum Matrix Composites

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 44 ◽  
Author(s):  
Peng-Xiang Zhang ◽  
Hong Yan ◽  
Wei Liu ◽  
Xiu-Liang Zou ◽  
Bin-Bing Tang
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Solution Treatment ◽  
Aluminum Matrix ◽  
Aging Treatment ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
X Ray ◽  
T6 Heat Treatment ◽  
The Matrix

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.

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
Keyword(s):  
Acoustic Streaming ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Aluminum Matrix Composites ◽  
Semisolid Slurry ◽  
Matrix Composites ◽  
Good Surface ◽  
Sic Particles ◽  
The Matrix ◽  
Cylindrical Parts

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.

Fatigue and Fracture Behavior of MMC in the HCF- and VHCF-Regime

2014 ◽  
Vol 783-786 ◽  
pp. 1597-1602 ◽  
Author(s):  
Matthias Wolf ◽  
Guntram Wagner ◽  
Dietmar Eifler
Keyword(s):  
Crack Initiation ◽  
Base Alloy ◽  
Early Stage ◽  
Fatigue Behavior ◽  
Aluminum Matrix ◽  
Matrix Alloy ◽  
Dissipated Energy ◽  
Aluminum Matrix Composites ◽  
Initiation Point ◽  
The Matrix

Aluminum matrix composites (AMCs) are characterized by improved mechanical properties in comparison to their unreinforced matrix alloys. But the knowledge about the fatigue behavior of AMCs in the HCF-and in the VHCF-regime is limited until now. Due to this AMC225xe and AMC xfine225 with an average SiC particle content of 25 vol.-% and particle sizes of 2.5 μm and 0.7 μm, respectively, as well as the base alloy AA2124 were fatigued up to 1010 cycles using the ultrasonic testing facility of the type "UltraFast-WKK-Kaiserslautern".To describe the fatigue behavior of the specimens several measuring devices were used to monitor and record the central process parameters. A very sensitive value to detect specimen failure at an early stage is the dissipated energy which can be determined as the integral of the generator power depending on the ultrasonic pulse time.In comparison to AA2124 the investigated AMCs have shown a considerably enhanced fatigue performance for stress amplitudes higher than 140 MPa. But below this stress amplitude for the matrix alloy run outs at 1010 cycles were realized whereas the AMCs failed at lower number of cycles still at lower stress amplitudes. Moreover, while crack initiation of the matrix alloy in all cases started at the surface for the AMCs the crack initiation point changes from surface to subsurface for more than 107 cycles. The subsurface failures of the composites were caused by microstructural inhomogeneities which could be identified with EDX and micro-CT as particle clusters and copper-iron-rich inclusions.

scholarly journals Titanium Dioxide Coated Graphene Nanosheets as a Reinforcement in Aluminum Matrix Composites Based on Pressure Sintering Process

2020 ◽  
Author(s):  
Zheng-Hua Guo ◽  
Qingjie Wu ◽  
Ning Li ◽  
Li-Hong Jiang ◽  
Wen He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Load Transfer ◽  
Graphene Nanosheets ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Powder Metallurgy Method ◽  
Matrix Composites ◽  
The Matrix ◽  
Coating Layers

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.

scholarly journals Corrosion Resistance of Al/SiC Laser Cladding Coatings on AA6082

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 673
Author(s):  
Ainhoa Riquelme ◽  
Pilar Rodrigo ◽  
María Dolores Escalera-Rodríguez ◽  
Joaquín Rams
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Laser Cladding ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
The Matrix ◽  
Corrosion Mechanisms ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Aluminum matrix composites reinforced with silicon carbide particles (SiCp) were deposited by laser cladding on AA6082 aluminum alloy. Different compositions of the matrix of the composites coating were used and different amounts of Si and Ti were added to a base of Al-12Si in order to control the reactivity between molten aluminum and SiCp during laser cladding. The corrosion behavior of the coatings deposited was evaluated in 3.5 wt.% NaCl solution using gravimetric analyses and electrochemical polarization tests. The corrosion products observed were Al(OH)3 and Al2O3, and they formed a layer that limited the evolution of corrosion. However, the presence of discontinuities in it reduced the corrosion resistance of the coating. The corrosion mechanisms were different depending on the coating composition. The addiction of Ti to the alloy allowed for better corrosion behavior for the composite coating than that of the aluminum substrate.

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