Structural and Morphological Characteristics of the Friction Surfaces of In-Situ Cast Aluminum Matrix Composites

Author(s):  
E. S. Prusov ◽  
V. B. Deev ◽  
A. V. Aborkin ◽  
E. Kh. Ri ◽  
E. M. Rakhuba
2021 ◽  
Vol 87 (5) ◽  
pp. 34-42
Author(s):  
N. B. Podymova ◽  
I. E. Kalashnikov ◽  
L. I. Kobeleva

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.


2015 ◽  
Vol 787 ◽  
pp. 583-587 ◽  
Author(s):  
V. Mohanavel ◽  
K. Rajan ◽  
K.R. Senthil Kumar

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.


1999 ◽  
Vol 14 (11) ◽  
pp. 4246-4250
Author(s):  
H. J. Brinkman ◽  
J. Duszczyk ◽  
L. Katgerman

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.


2018 ◽  
Vol 188 ◽  
pp. 03002
Author(s):  
Ekaterini Chantziara ◽  
Konstantinos Lentzaris ◽  
Angeliki G. Lekatou ◽  
Alexander E. Karantzalis

The main concept behind this work is to further enhance the attractive properties of aluminum by fabricating Al - WC composites and evaluating them in terms of their solid particle erosion response. Aluminum Matrix Composites (AMCs) were produced by the addition of submicron sized WC particles (up to 2.5vol %) into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to minimize particle clustering. Extensive presence of in-situ intermetallic phases (Al4W, Al5W, Al12W, Al3(Ti,W), Al3Ti) was observed in the cast products. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Solid particle erosion experiments were carried out for impact angles of 30°, 60° and 90°, using angular Al2O3 particles as the eroding medium and under 5 bar spraying pressure. The erosion rate was calculated by measuring the mass loss and the eroded surfaces were examined with SEM-EDX. Increased erosion resistance was observed for low particle additions (≤ 1.0 vol%WC). Finally, a possible erosion mechanism was proposed based on the material’s microstructural and morphological characteristics.


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

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