scholarly journals Synthesis of Micro- and Nanoparticles of Metal Oxides and Their Application for Reinforcement of Al-Based Alloys

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
S. Vorozhtsov ◽  
I. Zhukov ◽  
A. Vorozhtsov ◽  
A. Zhukov ◽  
D. Eskin ◽  
...  
Keyword(s):  
Particle Size ◽  
Composite Material ◽  
Comparative Analysis ◽  
Al Alloy ◽  
Ultrasonic Processing ◽  
Plasma Chemical ◽  
Chemical Methods ◽  
Chemical And Phase Compositions ◽  
Nanoparticles Of Metal Oxides ◽  
Special Master

This paper presents a comparative analysis of morphology, chemical and phase compositions, and particle size distribution of nanopowders produced by electric explosion of wire (EEW) and plasma-chemical methods. The possibility of introduction of Al2O3particles into Al alloy by means of a special master alloy and with ultrasonic processing is shown. The improvement of tensile properties of an Al-based composite material reinforced with 0.1 wt% of EEW Al2O3is demonstrated.

scholarly journals A Thermally Conductive Pt/AAO Catalyst for Hydrogen Passive Autocatalytic Recombination

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 491
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Aleksander A. Malakhov ◽  
Dmitri G. Bessarabov
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Combustion Temperature ◽  
Volume Fraction ◽  
Morphological Characteristics ◽  
Al Alloy ◽  
Impregnation Method ◽  
Case Scenario ◽  
Worst Case ◽  
Thermal Distribution

In this study, a Pt/anodized aluminum oxide (AAO) catalyst was prepared by the anodization of an Al alloy (Al6082, 97.5% Al), followed by the incorporation of Pt via an incipient wet impregnation method. Then, the Pt/AAO catalyst was evaluated for autocatalytic hydrogen recombination. The Pt/AAO catalyst’s morphological characteristics were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average Pt particle size was determined to be 3.0 ± 0.6 nm. This Pt/AAO catalyst was tested for the combustion of lean hydrogen (0.5–4 vol% H2 in the air) in a recombiner section testing station. The thermal distribution throughout the catalytic surface was investigated at 3 vol% hydrogen (H2) using an infrared camera. The Al/AAO system had a high thermal conductivity, which prevents the formation of hotspots (areas where localized surface temperature is higher than an average temperature across the entire catalyst surface). In turn, the Pt stability was enhanced during catalytic hydrogen combustion (CHC). A temperature gradient over 70 mm of the Pt/AAO catalyst was 23 °C and 42 °C for catalysts with uniform and nonuniform (worst-case scenario) Pt distributions. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used to compare the experimentally observed and numerically simulated thermal distribution of the Pt/AAO catalyst. The effect of the initial H2 volume fraction on the combustion temperature and conversion of H2 was investigated. The activation energy for CHC on the Pt/AAO catalyst was 19.2 kJ/mol. Prolonged CHC was performed to assess the durability (reactive metal stability and catalytic activity) of the Pt/AAO catalyst. A stable combustion temperature of 162.8 ± 8.0 °C was maintained over 530 h of CHC. To confirm that Pt aggregation was avoided, the Pt particle size and distribution were determined by TEM before and after prolonged CHC.

Influence of Rubber Particle Size on Functional Properties of a Composite Material Based on Scrap Tires and a Polymer Binder

2020 ◽  
Vol 850 ◽  
pp. 107-111
Author(s):  
Laimonis Mālers ◽  
Agnija Cirvele
Keyword(s):  
Particle Size ◽  
Composite Material ◽  
Functional Properties ◽  
Material Properties ◽  
Rubber Particle ◽  
Polymer Binder ◽  
Scrap Tires ◽  
Elongation At Break ◽  
Rubber Particles ◽  
Purposeful Selection

Functional properties of composite material based on mechanically grinded scrap tires with different particle size of fractioned crumb and polyurethane type polymer binder were investigated to estimate influence of rubber particles size and content on composite material properties (Shore C hardness, compressive stress at 10 % deformation, tensile strength, elastic modulus and elongation at break, apparent density). Optimization possibilities of composite material consisting of rubber particles with different sizes or fractions were investigated. The obtained results show that variation of composition of the composite material by changing size of rubber granulate have definite influence on selected properties of the material. Purposeful selection and mutual combination of rubber particles size included in material can ensure desirable and predictable mechanical properties of composite material.

Isothermal Rolling of Mg-Based Laminated Composites Made by Explosion Cladding

2010 ◽  
Vol 443 ◽  
pp. 614-619 ◽  
Author(s):  
Xin Ping Zhang ◽  
Ming Jen Tan ◽  
Ting Hui Yang ◽  
Jing Tao Wang
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Finite Element Methods ◽  
Strain Distribution ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Al Alloy ◽  
Layer Composite

Rolling of Al-Mg-Al tri-layer composite material fabricated by the explosion cladding method was simulated using finite element methods. The rolling temperature was determined based on the flow stresses of AZ31 magnesium alloy and 7075 Al alloy at elevated temperature. The strain distribution in the plates during rolling and effects of the reduction ratio on the separation in the Al/Mg/Al laminate were studied. The simulation agrees with experimental results.

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