Impact of the reinforced metal structure on the mechanical properties foamed aluminium composites at the load

Abstract This paper is an experimental study of the quasi-static mechanical compressive properties of the reinforced closed-cell aluminum alloy foams with different cell orientations at different strain rates. The reinforced foam samples were obtained via the powder metallurgical route. The results of the compression tests revealed that the deformation behavior and mechanical properties of foamed aluminum composites are highly dependent on the orientation of the reinforcing mesh. Differences in the deformation behavior of foams appear to be influenced by the mechanical properties of the matrix material, by foam deformation mechanisms, and by the mechanical properties of the reinforcement. The yield stress, plateau stress, densification stress, and energy absorption capacity of unreinforced foam samples improved linearly with increasing strain rate due to dynamic recrystallization and softening of the foam matrix material. The reinforced foam samples exhibit nonlinear deformation behavior. It was also found that the mechanical properties reduction of transverse reinforced foams was slightly lower compared to foams with longitudinal reinforcement at varying strain rates because of the large contribution of the mechanical properties of the reinforcement. The results of the present study can be employed to modelling and obtain impact-resistant fillers for complex structures in transport construction.

Download Full-text

Hot Deformation Behavior of as-Cast AZ61 Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.574 ◽

2013 ◽

Vol 750-752 ◽

pp. 574-578

Author(s):

Zhong Xue Feng ◽

Qing Nan Shi ◽

Fu Sheng Pan ◽

Jun Tan ◽

Liang Wei Chen ◽

...

Keyword(s):

Magnesium Alloy ◽

Deformation Behavior ◽

High Strain ◽

Shear Zones ◽

Strain Rates ◽

Compression Tests ◽

Hot Deformation Behavior ◽

Thermal Compression ◽

Az61 Magnesium Alloy ◽

The Matrix

Thermal compression tests of AZ61 magnesium alloy were performed at deformation temperature 25-400°C with strain rates ranged from 0.02 to 20 s-1, and the microstructure was studied. The conventional dynamic recrystallization (DRX) and shear zones were observed on grain boundaries at temperatures above 200°C. The shear zone and the temperature rise are considered to be responsible for the fracture of specimens. For the large internal stress concentration in the shear zones and the deformation incompatibility between matrix and shear zones, the fracture grew along with the shear zones and the failure occurred in the large deformation field of the matrix at the high strain rate 20 s-1 even at 400°C.

Download Full-text

Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Materials ◽

10.3390/ma14020249 ◽

2021 ◽

Vol 14 (2) ◽

pp. 249

Author(s):

Przemysław Rumianek ◽

Tomasz Dobosz ◽

Radosław Nowak ◽

Piotr Dziewit ◽

Andrzej Aromiński

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Strain Rate ◽

Energy Absorption ◽

Experimental Tests ◽

Absorption Capacity ◽

Strain Rates ◽

Foam Density ◽

Energy Absorption Capacity ◽

Closed Cell

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

Download Full-text

Hot Deformation Behavior of a Ni-Based Superalloy with Suppressed Precipitation

Metals ◽

10.3390/met11040605 ◽

2021 ◽

Vol 11 (4) ◽

pp. 605

Author(s):

Franco Lizzi ◽

Kashyap Pradeep ◽

Aleksandar Stanojevic ◽

Silvana Sommadossi ◽

Maria Cecilia Poletti

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Hot Deformation ◽

Strain Rates ◽

Compression Tests ◽

Deformation Bands ◽

Stress Softening ◽

Relative Stress ◽

The Matrix ◽

Thermomechanical Processes

Inconel®718 is a well-known nickel-based super-alloy used for high-temperature applications after thermomechanical processes followed by heat treatments. This work describes the evolution of the microstructure and the stresses during hot deformation of a prototype alloy named IN718WP produced by powder metallurgy with similar chemical composition to the matrix of Inconel®718. Compression tests were performed by the thermomechanical simulator Gleeble®3800 in a temperature range from 900 to 1025 °C, and strain rates scaled from 0.001 to 10 s−1. Flow curves of IN718WP showed similar features to those of Inconel®718. The relative stress softening of the IN718WP was comparable to standard alloy Inconel®718 for the highest strain rates. Large stress softening at low strain rates may be related to two phenomena: the fast recrystallization rate, and the coarsening of micropores driven by diffusion. Dynamic recrystallization grade and grain size were quantified using metallography. The recrystallization grade increased as the strain rate decreased, although showed less dependency on the temperature. Dynamic recrystallization occurred after the formation of deformation bands at strain rates above 0.1 s−1 and after the formation of subgrains when deforming at low strain rates. Recrystallized grains had a large number of sigma 3 boundaries, and their percentage increased with strain rate and temperature. The calculated apparent activation energy and strain rate exponent value were similar to those found for Inconel®718 when deforming above the solvus temperature.

Download Full-text

Microstructural analysis of Al6063/sic with calcium additives for hardness enhancement

MATEC Web of Conferences ◽

10.1051/matecconf/201822503007 ◽

2018 ◽

Vol 225 ◽

pp. 03007

Author(s):

Balaji Bakthavatchalam ◽

Khairul Habib ◽

Namdev Patil ◽

Omar A Hussein

Keyword(s):

Mechanical Properties ◽

Silicon Carbide ◽

Matrix Material ◽

Microstructural Analysis ◽

Wear Loss ◽

Alloying Element ◽

Silicon Phase ◽

High Durability ◽

The Matrix ◽

Al6063 Alloy

Microstructural Analysis plays an important role in enhancing the mechanical properties of metals and composites. Usually Aluminium Silicon Carbide (Al6063/SiC) alloys are mixed with strontium, sodium and antimony for high durability even though they are toxic and costly. As an alternative calcium is used as an alloying element to improve the mechanical property of Al6063/Sic alloy. In this paper Al6063 is chosen as the matrix material while Sic is used as a reinforcement where calcium powder is added to modify the silicon phase of the composite. Finally, concentration of Silicon carbide is varied from 0 to 150 mg to produce four specimens of Al6063 alloy and it is subjected to microstructure analysis which showed the reduction of grain size and therefore improvement in the hardness from 52.9 HV to 58.4 HV and decrease in the wear loss from 3.97 to 3.27 percentage.

Download Full-text

Physical and Mechanical Properties of Composites with Aluminum Alloy Matrix Designed for Metal Forming

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.212.59 ◽

2013 ◽

Vol 212 ◽

pp. 59-62 ◽

Cited By ~ 2

Author(s):

Jerzy Myalski ◽

Jakub Wieczorek ◽

Adam Płachta

Keyword(s):

Mechanical Properties ◽

Metal Forming ◽

Matrix Material ◽

Physical And Mechanical Properties ◽

Mechanical Mixing ◽

Alloy Matrix ◽

Segregation Process ◽

The Matrix ◽

Glass Carbon ◽

Properties Of Composites

The change of matrix and usage of the aluminum alloys designed for the metal forming in making the composite suspension allows to extend the processing possibility of this type of materials. The possibility of the metal forming of the composites obtained by mechanical mixing will extend the range of composite materials usage. Applying of the metal forming e.g. matrix forging, embossing, pressing or rolling, will allow to remove the incoherence of the structure created while casting and removing casting failures. In order to avoid the appearance of the casting failures the homogenization conditions need to be changed. Inserting the particles into the matrix influences on the shortening of the composite solidification. The type of the applied particles influenced the sedimentation process and reinforcement agglomeration in the structure of the composite. Opposite to the composites reinforced with one-phase particles applying the fasess mixture (glassy carbon and silicon carbide) triggered significant limitation in the segregation process while casting solidification. Inserting the particles into the AW-AlCu2SiMn matrix lowers the mechanical properties tension and impact value strength. The most beneficial mechanical properties were gained in case of heterofasess composites reinforced with the particle mixture of SiC and glass carbon. The chemical composition of the matrix material (AW-AlCu2SiMn) allows to increase additionally mechanical characteristics by the precipitation hardening reached through heat casting forming.

Download Full-text

Mechanical Compression and Crushing Properties of a Straw-Lime Material

10.4028/www.scientific.net/cta.1.227 ◽

2022 ◽

Author(s):

Parmo Parmo ◽

Jean-Luc Hanus ◽

Naima Belayachi ◽

Patrice Bailly

Keyword(s):

Mechanical Properties ◽

Linear Part ◽

Strain Curve ◽

Image Correlation ◽

Compression Tests ◽

Stress Plateau ◽

Speed Test ◽

Binder Ratio ◽

Parallel Direction ◽

Strain Stress

The aim of this study was to determine the compressive mechanical properties and the energy absorption characteristics of a bio-composite material based on lime, wheat straw, and additives (protein and entraining agent). The selected samples with fiber to binder ratio of 30% were subjected to compression tests at different strain rates (1 mm/min, 10 mm/min, and 100 mm/min), in the perpendicular and parallel directions to fiber orientation. Image analysis supported with Digital Image Correlation (DIC) method is performed to follow longitudinal and lateral deformations, thus making it possible to evaluate elastic properties. The results show that the highest density and compressive strength in the parallel direction are ~349 kg/m3 and ~0.101 MPa, respectively. The perpendicular specimens at 100 mm/min of speed test showed the highest values of densification strain, stress plateau, energy efficiency, and absorbed-energy of 47.27%, 0.32 MPa, 16.98 %, and 13.84 kJ/m2, respectively. The values of Young’s modulus identified with DIC are significantly different from those determined by the slope of the linear part of the stress-strain curve. A slight influence of strain rate on mechanical properties is observed.

Download Full-text

Strain-Rate-Dependent Deformation Behavior and Mechanical Properties of a Multi-Phase Medium-Manganese Steel

Metals ◽

10.3390/met9030344 ◽

2019 ◽

Vol 9 (3) ◽

pp. 344 ◽

Cited By ~ 15

Author(s):

Simon Sevsek ◽

Christian Haase ◽

Wolfgang Bleck

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Deformation Behavior ◽

Rate Sensitivity ◽

Manganese Steel ◽

Strain Rates ◽

Rate Dependent ◽

Medium Manganese Steel ◽

Multi Phase

The strain-rate-dependent deformation behavior of an intercritically annealed X6MnAl12-3 medium-manganese steel was analyzed with respect to the mechanical properties, activation of deformation-induced martensitic phase transformation, and strain localization behavior. Intercritical annealing at 675 °C for 2 h led to an ultrafine-grained multi-phase microstructure with 45% of mostly equiaxed, recrystallized austenite and 55% ferrite or recovered, lamellar martensite. In-situ digital image correlation methods during tensile tests revealed strain localization behavior during the discontinuous elastic-plastic transition, which was due to the localization of strain in the softer austenite in the early stages of plastic deformation. The dependence of the macroscopic mechanical properties on the strain rate is due to the strain-rate sensitivity of the microscopic deformation behavior. On the one hand, the deformation-induced phase transformation of austenite to martensite showed a clear strain-rate dependency and was partially suppressed at very low and very high strain rates. On the other hand, the strain-rate-dependent relative strength of ferrite and martensite compared to austenite influenced the strain partitioning during plastic deformation, and subsequently, the work-hardening rate. As a result, the tested X6MnAl12-3 medium-manganese steel showed a negative strain-rate sensitivity at very low to medium strain rates and a positive strain-rate sensitivity at medium to high strain rates.

Download Full-text

Mechanical Properties of Dye 3 Greenland Deep Ice Cores

Annals of Glaciology ◽

10.3189/1984aog5-1-1-8 ◽

1984 ◽

Vol 5 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Nobuhiko Azuma ◽

Akira Higashi

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Power Law ◽

Ice Core ◽

Ice Cores ◽

Uniaxial Stress ◽

Strain Rates ◽

Compression Tests ◽

Polycrystalline Ice ◽

Relationship Of

Uniaxial compression tests were carried out with specimens cut from several deep ice cores obtained at Dye 3, Greenland, in 1980 and 1981. The power law relationship of = Αση was obtained between the uniaxial strain-rate and the uniaxial stress σ. In a range of strain-rates between 10−8 and 10−7 s−1, the value of the power n for samples with strong single maximum fabric was approximately 4, significantly larger than the value of 3 which has been generally accepted from experiments using artificial polycrystalline ice. A work-hardening effect was found in the ice-core samples taken from a depth of 1900 m, which had a smaller grain size than the others. Recrystallization occurred when the temperature of the specimen was raised during the test and this ultimately caused the formation of the so-called diamond pattern ice fabric.

Download Full-text

Thermal Deformation Behavior and Processing Map of Al-Mg-Er Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.30 ◽

2018 ◽

Vol 913 ◽

pp. 30-36

Author(s):

Ran Liu ◽

Hui Huang ◽

Ya Liu ◽

Li Rong

Keyword(s):

Flow Stress ◽

Deformation Behavior ◽

Deformation Temperature ◽

Material Model ◽

Instability Criterion ◽

Strain Rates ◽

Processing Maps ◽

Hot Workability ◽

Compression Tests ◽

Dynamic Material Model

To study the hot deformation behavior of Al-Mg-Er alloy, hot compression tests were conducted on a Gleeble-1500D thermal simulator at the temperature range of 200-500°C with the strain rates from 0.001 to 10s-1. With the increase in the deformation temperature and the decrease in strain rates, the flow stress of the Al-Mg-Er alloy decreased. Processing maps were constructed to study on hot workability characteristics. The results showed that the flow stress curves exhibited the typical dynamic recrystallization characteristics and the stress decreased with the increase of deformation temperature and the decrease of strain rate. Moreover, the processing maps were established on the basis of dynamic material model and Prasad’s instability criterion.

Download Full-text

Effect of Reactive SPS on the Microstructure and Properties of a Dual-Phase Ni-Al Intermetallic Compound and Ni-Al-TiB2 Composite

Materials ◽

10.3390/ma13245668 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5668

Author(s):

Paweł Hyjek ◽

Iwona Sulima ◽

Piotr Malczewski ◽

Krzysztof Bryła ◽

Lucyna Jaworska

Keyword(s):

Intermetallic Compound ◽

Tribological Properties ◽

Matrix Material ◽

Dual Phase ◽

Compression Tests ◽

Two Phase ◽

Alloy Matrix ◽

Plastic Properties ◽

Mechanical And Tribological Properties ◽

The Matrix

As part of the tests, a two-phase NiAl/Ni3Al alloy and a composite based on this alloy with 4 vol% addition of TiB2 were produced by the reactive FAST/SPS (Field Assisted Sintering Technology/Spark Plasma Sintering) sintering method. The sintering process was carried out at 1273 K for 30 s under an argon atmosphere. The effect of reactive SPS on the density, microstructure, and mechanical and tribological properties of a dual-phase Ni-Al intermetallic compound and Ni-Al-TiB2 composite was investigated. Products obtained were characterized by a high degree of sintering (over 99% of the theoretical density). The microstructure of sinters was characterized by a large diversity, mainly in regard to the structure of the dual-phase alloy (matrix). Compression tests showed satisfactory plastic properties of the manufactured materials, especially at high temperature (1073 K). For both materials at room temperature, the compressive strength was over 3 GPa. The stress–strain curves were observed to assume a different course for the matrix material and composite material, including differences in the maximum plastic flow stress depending on the test temperature. The brittle-to-ductile transition temperature was determined to be above 873 K. The research has revealed differences in the physical, mechanical and tribological properties of the produced sinters. However, the differences favourable for the composite were mostly the result of the addition of TiB2 ceramic particles uniformly distributed on grain boundaries.

Download Full-text