Fabrication and microstructure of in situ Al2O3 decomposed from Al2(SO4)3-reinforced aluminum matrix composites

2003 ◽  
Vol 57 (11) ◽  
pp. 1712-1715 ◽  
Author(s):  
Ouyang Liuzhang ◽  
Luo Chengping ◽  
Sui Xiandong ◽  
Zeng Meiqin ◽  
Zhu Min
Keyword(s):  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites

Study on Mechanical Properties of AA6351 Alloy Reinforced with Titanium Di-Boride (TiB2) Composite by In Situ Casting Method

2015 ◽  
Vol 787 ◽  
pp. 583-587 ◽  
Author(s):  
V. Mohanavel ◽  
K. Rajan ◽  
K.R. Senthil Kumar
Keyword(s):  
Tensile Strength ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Scanning Electron Micrographs ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
In Situ Reaction ◽  
Halide Salts ◽  
Scanning Electron

In the present study, an aluminum alloy AA6351 was reinforced with different percentages (1, 3 and 5 wt %) of TiB2 particles and they were successfully fabricated by in situ reaction of halide salts, potassium hexafluoro-titanate and potassium tetrafluoro-borate, with aluminium melt. Tensile strength, yield strength and hardness of the composite were investigated. In situ reaction between the inorganic salts K2TiF6 and KBF4 to molten aluminum leads to the formation of TiB2 particles. The prepared aluminum matrix composites were characterized using X-ray diffraction and scanning electron microscope. Scanning electron micrographs revealed a uniform dispersal of TiB2 particles in the aluminum matrix. The results obtained indicate that the hardness and tensile strength were increased with an increase in weight percentages of TiB2 contents.

Reactive hot pressing of aluminum matrix composites

1999 ◽  
Vol 14 (11) ◽  
pp. 4246-4250
Author(s):  
H. J. Brinkman ◽  
J. Duszczyk ◽  
L. Katgerman
Keyword(s):  
Hot Pressing ◽  
Adverse Reactions ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Processing Step ◽  
Exothermic Process ◽  
Composite Product ◽  
Reactive Hot Pressing

A method is described for the production of dense aluminum matrix composites from elemental powders in one processing step by reactive hot pressing (RHP). It encompasses both the exothermic conversion of reactants to composite product and the following hot compaction of the porous composite product. The RHP method described in this paper takes into account the gas evolution accompanying the exothermic process, ensures complete conversion of reactants, and avoids adverse reactions between aluminum matrix and graphite tooling material. In situ sample temperature measurements enable proper process control, in particular the timing of the full densification step of the hot reaction product.

Laser-ultrasonic study of the local porosity of reactive cast aluminum-matrix composites

2021 ◽  
Vol 87 (5) ◽  
pp. 34-42
Author(s):  
N. B. Podymova ◽  
I. E. Kalashnikov ◽  
L. I. Kobeleva
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Aluminum Matrix ◽  
Amplitude Distribution ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Cast Aluminum ◽  
Laser Ultrasonic ◽  
Local Porosity

One of the most critical manufacturing defects of cast metal-matrix composites is a non-uniform porosity distribution over the composite volume. Unevenness of the distribution leads not only to local softening, but also plays a key role in the evolution of the damage process under the external loads. The goal of the study is to apply a new laser-ultrasonic method to in-situ study of a local porosity in reactive cast aluminum-matrix composites. The proposed method is based on statistical analysis of the amplitude distribution of backscattered broadband pulses of longitudinal ultrasonic waves in the studied materials. Laser excitation and piezoelectric detection of ultrasound were carried out using a laser-ultrasonic transducer. Two series of reactive cast aluminum-matrix composites were analyzed: reinforced by in situ synthesized Al3Ti intermetallic particles in different volume concentrations and by Al3Ti added with synthetic diamond nanoparticles. It is shown that for both series of the composites, the amplitude distribution of backscattered ultrasonic pulses is approximated by the Gaussian probability distribution applicable for statistics of large number of independent random variables. The empirical dependence of the half-width of this distribution on the local porosity in composites of two series is approximated by the same nearly linear function regardless of the size and fraction of reinforcing particles. This function was used to derive the formula for calculation of the local porosity in the studied composites. The developed technique seems to be promising in revealing potentially dangerous domains with high porosity in reactive-cast metal-matrix composites.

Studies on the grinding force, size effect, surface texture, and mechanism of material removal in the grinding of AA6061-TiB2/ZrB2 in situ composite

2019 ◽  
Vol 2 (2) ◽  
pp. 152-166
Author(s):  
A. Mahamani
Keyword(s):  
Size Effect ◽  
Surface Integrity ◽  
Material Removal ◽  
Surface Defects ◽  
Aluminum Matrix ◽  
Grinding Force ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Grinding Conditions

Machining and conversion of aluminum matrix composites into a desired shape with accuracy has been a challenge for many years. Grinding is a process aimed at achieving better-quality surface finish along with reasonable rate of material removal. The present article describes the influence of operating parameters on the tangential grinding force, size effect, and surface integrity in the grinding of in situ aluminum matrix composites using various grinding wheels. The material removal mechanism of the in situ composite under different grinding conditions is established. Experimental results show that the grinding operating parameters have significant influence on the tangential grinding force, size effect, surface integrity, and material removal. Scanning electron and atomic force microscopy findings indicate presence of numerous surface defects on the grounded surface under all grinding conditions. Diamond grinding wheel outperformed the CBN and Al2O3 wheels by requiring lower grinding force and specific grinding energy and generating lower surface defects. Surface defects, including grinding striation, delamination, and ridge formation are unavoidable under all machining conditions. However, the aforementioned surface defects indicate the ductile mode of material removal at all experimental conditions. Undeformed chip thickness under various grinding conditions plays a significant role in material removal and surface generation. These findings help to understand the mechanism of material removal in machining of in situ composites under various grinding conditions, which helps in attaining the economic production rate without compromising the surface integrity.

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