scholarly journals Enhanced Mechanical Properties of Carbon Nanotube/Aluminum Composites Fabricated by Powder Metallurgical and Repeated Hot-Rolling Techniques

2020 ◽  
Vol 4 (4) ◽  
pp. 169
Author(s):  
Hideaki Tsukamoto
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Potassium Carbonate ◽  
Hot Rolling ◽  
Inorganic Salt ◽  
High Strength ◽  
Sonication Time ◽  
Aluminum Composites ◽  
Dispersing Agent

This research aimed to fabricate lightweight and high-strength carbon nanotube (CNT)/aluminum (Al) composites by powder metallurgical and repeated hot-rolling techniques. The fabrication was conducted in three steps: (1) CNT dispersion, (2) preparation of CNT/Al compacts by powder metallurgical slurry methods, and (3) strengthening and refining of CNT/Al composites by repeated hot rolling. The processes of dispersion of CNTs were carried out with dimethylacetamide as a solvent and potassium carbonate as a dispersing agent, which is an inorganic salt, under ultrasonic sonication conditions. Effect of sonication time on dispersion states and mechanical properties was also examined.

Improved Tensile Strength of Carbon Nanotube Reinforced Aluminum Composites Processed by Powder Metallurgy

2012 ◽  
Vol 500 ◽  
pp. 651-656 ◽  
Author(s):  
Jin Zhi Liao ◽  
Ming Jen Tan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Nanotube ◽  
Powder Metallurgy ◽  
Hot Rolling ◽  
Hot Extrusion ◽  
Significant Enhancement ◽  
Aluminum Composites ◽  
Thermal Mismatch ◽  
Pure Matrix

Carbon nanotube (CNT) reinforced aluminum (Al) composites were synthesized using the powder metallurgy (P/M) technique, combined with hot extrusion and hot rolling. 0-2.0wt.% of CNTs were added as reinforcements. The effect of CNTs on the mechanical properties of Al was investigated and a significant enhancement in tensile strength was obtained compared with the pure matrix. The improved strength was analyzed based on (i) Orowan strengthening, (ii) thermal mismatch between CNTs and matrix, and (iii) load partition effect due to the CNTs.

scholarly journals Study of the thermal treatment modes influence on the forming of microstructure and specified complex of mechanical properties of high-strength sheet product with guaranteed level of hardness (400–450 HB) of low-alloyed steel

2019 ◽  
Vol 75 (4) ◽  
pp. 480-487
Author(s):  
M. Yu. Matrosov ◽  
P. G. Martynov ◽  
A. V. Mitrofanov ◽  
K. Yu. Barabash ◽  
T. V. Goroshko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fine Structure ◽  
Thermal Treatment ◽  
Hot Rolling ◽  
High Strength ◽  
Controlled Rolling ◽  
Alloyed Steel ◽  
Accelerated Cooling ◽  
Cold Forming ◽  
Low Alloyed Steel

High-strength sheet product of low-alloyed steel, used at manufacturing of heavy-loaded structures, must have, apart from wear resistance, high toughness, good weldability, ability to hot and cold forming, machinability and low cost. Combination of these properties based on forming fine grain austenite structure before the martensitic transformation at definite its thermal treatment modes. Results of study of microstructure, fine structure and mechanical properties of high-strength boron-containing low-alloyed steel after different technological methods of the rolled product manufacturing presented: high-temperature hot rolling and twostages controlled rolling with accelerated cooling followed by thermal treatment – quenching with tempering. Variants of optimal modes of thermal treatment determined, providing combination of high level of impact toughness under negative temperatures, hardness and strength properties of sheet product. The two considered in the article technological variants, comprising treatment of low-alloyed steel with boron (hot rolling and two-stages controlled rolling with accelerated cooling) followed by thermal treatment results in forming fine structure of tempered martensite, which provides high mechanical properties, meeting the made requirements. Depending on the heating temperature before quenching in the range 770–950 °С, the morphology of the actual steel grain is changing from elongated to equiaxed, which is connected with the metal recrystallization process during heating after plastic deformation. The study results obtained allow to optimize the thermal treatment processes of sheet product of low-alloyed boron containing steel for particular conditions of application.

scholarly journals Tribological Characterization of Carbon Nanotube/Aluminum Functionally Graded Materials Fabricated by Centrifugal Slurry Methods

2021 ◽  
Vol 5 (10) ◽  
pp. 254
Author(s):  
Hideaki Tsukamoto
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Functionally Graded Materials ◽  
Potassium Carbonate ◽  
High Performance ◽  
Functionally Graded ◽  
Graded Materials ◽  
Tribological Characterization ◽  
Al Matrix

Although carbon nanotube (CNT) is a promising material due to its excellent mechanical and functional properties, CNT has not been effectively used for high performance composites due to the degradation of its mechanical properties as a result of insufficient dispersibility of CNT in its matrix. In this study, CNT/aluminum (Al) matrix functionally graded materials (FGMs) were fabricated by centrifugal slurry methods. The dispersion of CNT was carried out with the solvent of dimethylacetamide (DMAs), and the dispersant of potassium carbonate (K2CO3) under ultrasonic sonication conditions. Tribological characteristics on the FGMs were investigated using a ball-on-disk tribometer. It was demonstrated that the presence of CNT contributed to an increase of the coefficients of friction and an enhancement of wear resistances.

Failure Analysis of Si3N4 Rolls for Wire Hot Rolling by Numerical Simulation of Thermal and Mechanical Stresses

2005 ◽  
Vol 290 ◽  
pp. 94-101 ◽  
Author(s):  
Markus Lengauer ◽  
Robert Danzer ◽  
Domagoj Rubeša ◽  
Walter Harrer ◽  
W. Zleppnig
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Silicon Nitride ◽  
Hot Rolling ◽  
Rolling Mill ◽  
Subcritical Crack Growth ◽  
Thermal Stresses ◽  
High Strength ◽  
Induced Stresses ◽  
Observed Damage

Silicon nitride rolls for wire hot rolling have been tested in the rolling mill. After short employment for processing of ultra-high strength materials, cracks appeared in the roll calibre, which limited further application of the rolls. In order to find out possible causes for the damage, relevant mechanical properties of the roll have been determined and thermally and mechanically induced stresses were assessed by numerical simulation. It has been found that thermal stresses are of little relevance, whereas mechanically induced stresses are high enough to enhance subcritical crack growth resulting in the development of the macroscopic cracks, so that the observed damage of the rolls could have been adequately explained. One further result of the analysis was that flaws induced by grinding are decisive for the service time of ceramic rolls, so that special attention has to be paid to the machining of the roll calibre.

Study on the Galvanealing Process for High Strength Low Alloying Auto Steel

2014 ◽  
Vol 692 ◽  
pp. 450-453
Author(s):  
Fang Fang ◽  
Li Xin Wang ◽  
Li Hui Wang ◽  
Fang Yi Sun
Keyword(s):  
Mechanical Properties ◽  
Hot Rolling ◽  
High Strength ◽  
Coiling Temperature ◽  
Research Results ◽  
Good Surface ◽  
Steel Making ◽  
Δ Phase ◽  
Resistance Performance

An industry trial high strength low alloying auto steel was undergone simulated continuous galvanealing processed. The research results show that, good surface and mechanical properties of matrix for the following galvanealing process were achieved by controlling the steel making, final and coiling temperature of hot rolling in minor fluctuation. When the experimental steels were galvanealed at 520°C and 20s in simulation, more plastic ζ phase, less brittle δ phase in the coating guaranteed good powdering resistance performance.

scholarly journals STUDY ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 42CrMo4/NANOS-BA® HIGH-STRENGTH CLAD PLATES AFTER THE PROCESS OF HOT ROLLING AND TWO-STAGE HEAT TREATMENT WITH ISOTHERMAL TRANSFORMATION

2021 ◽  
Vol 73 (1) ◽  
pp. 22-31
Author(s):  
Bartłomiej WALNIK ◽  
Dariusz Woźniak ◽  
Aleksandra NIESZPOREK ◽  
Mariusz ADAMCZYK
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hot Rolling ◽  
High Strength ◽  
Isothermal Transformation ◽  
Two Stage ◽  
Physical Experiments ◽  
Microstructure Examination ◽  
Steel Grades ◽  
Stage Heat Treatment

The aim of the study was to develop a technology for welding non-weldable 42CrMo4 and NANOS-BA® steel grades in the process of hot rolling and two-stage heat treatment. As a result of physical experiments carried out in a line for semi-industrial simulation of the production of metals and their alloys (LPS) and additional heat treatment, a durable combination of 42CrMo4 and NANOS-BA® steels with high mechanical properties was obtained, including: Rp0.2 = 1036 MPa, Rm = 1504 MPa and A = 10.9%, without microscopically visible cracks and other discontinuities in the joined surface. The quality of the 42CrMo4/NANOS-BA® clad plates produced in this way was assessed on the basis of microstructure examination as well as bending, shear and tensile strength tests.

Fabrication of Carbon Nanotube/ Aluminum Matrix Functionally Graded Materials Using Centrifugal Slurry Methods

2021 ◽  
Vol 878 ◽  
pp. 31-40
Author(s):  
Satoshi Namigata ◽  
Hideaki Tsukamoto
Keyword(s):  
Carbon Nanotube ◽  
Functionally Graded Materials ◽  
High Performance ◽  
Inorganic Salt ◽  
Aluminum Matrix ◽  
Functionally Graded ◽  
Graded Materials ◽  
Dispersing Agent ◽  
The Matrix ◽  
Al Matrix

Carbon nanotube (CNT) has received broad scientific and industrial attention due to their excellent mechanical and functional properties. However, CNT has not been effectively used for high performance composites because of degradation of mechanical properties due to insufficient dispersibility of CNT in the matrix. In this study, CNT/ aluminum (Al) matrix functionally graded materials (FGMs) have been focused on. The processes of dispersion of CNT have been carried out with the solvent of dimethylacetamide, and the dispersing agent of potassium carbonate, which is an inorganic salt, under ultrasonic sonication conditions. Centrifugal slurry methods have been applied to obtain gradient of content of CNT in CNT/ Al matrix FGMs. Tribological characteristics on CNT/ Al matrix FGMs have been investigated using a ball-on-disk tribometer. It has been demonstrated that CNT contributes to enhance wear resistances.

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