scholarly journals Combined Calorimetry, Thermo-Mechanical Analysis and Tensile Test on Welded EN AW-6082 Joints

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1396 ◽  
Author(s):  
Philipp Wiechmann ◽  
Hannes Panwitt ◽  
Horst Heyer ◽  
Michael Reich ◽  
Manuela Sander ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Thermal Analyses ◽  
Mechanical Analysis ◽  
Image Correlation ◽  
Ex Situ ◽  
Compression Tests ◽  
Depth Analysis ◽  
Welding Processes

Wide softening zones are typical for welded joints of age hardened aluminium alloys. In this study, the microstructure evolution and distribution of mechanical properties resulting from welding processes of the aluminium alloy EN AW-6082 (AlSi1MgMn) was analysed by both in-situ and ex-situ investigations. The in-situ thermal analyses included differential scanning calorimetry (DSC), which was used to characterise the dissolution and precipitation behaviour in the heat affected zone (HAZ) of welded joints. Thermo-mechanical analysis (TMA) by means of compression tests was used to determine the mechanical properties of various states of the microstructure after the welding heat input. The necessary temperature–time courses in the HAZ for these methods were measured using thermocouples during welding. Additionally, ex-situ tensile tests were done both on specimens from the fusion zone and on welded joints, and their in-depth analysis with digital image correlation (DIC) accompanied by finite element simulations serve for the description of flow curves in different areas of the weld. The combination of these methods and the discussion of their results make an essential contribution to understand the influence of welding heat on the material properties, particularly on the softening behaviour. Furthermore, the distributed strength characteristic of the welded connections is required for an applicable estimation of the load-bearing capacity of welded aluminium structures by numerical methods.

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

scholarly journals Mechanical Properties of a Typical Jurassic Shaximiao Sandstone Under Subzero and Deep in situ Temperature Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
R. He ◽  
L. He ◽  
B. Guan ◽  
C. M. Yuan ◽  
J. Xie ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Front ◽  
Image Correlation ◽  
Correlation Technique ◽  
Direct Tension ◽  
Reservoir Stimulation ◽  
The Difference ◽  
Lower Temperature ◽  
Highly Strained

Insight into the difference between the mechanical properties of rocks at low and in situ deep reservoir temperatures is vital for achieving a better understanding of fracking technologies with supercritical CO2 and liquid nitrogen. To address this issue, the fracking-related mechanical properties of the Shaximiao Formation sandstone (SS) were investigated through direct tension, uniaxial compression, and three-point bending fracture tests at a typical low temperature (Tlow) of −10°C and a reservoir temperature (Tin situ) of 70°C. The results showed that the tensile strength σt, compressive strength σc, and fracture toughness KIC of the SS were all higher at Tlow than at Tin situ, although to different extents. The KIC of the SS increased slightly more than σt at the lower temperature, while both σt and KIC of the SS increased significantly more than σc at the lower temperature. In addition to the strength, the stiffness (particularly the tensile stiffness) and the brittleness indices of SS were similarly higher at Tlow than at Tin situ. In situ monitoring using the digital image correlation technique revealed that a highly strained band (HSB) always appeared at the crack front. However, because of the inhomogeneous microstructure of the SS, the HSB did not always develop along the line connecting the notch tip to the loading point. This was a possible cause of the highly dispersed KIC values of the SS. The HSB at the crack front was notably narrower at Tlow than at Tin situ, suggesting that low temperatures suppress the plastic deformation of rocks and are therefore beneficial to reservoir stimulation.

Mechanical Compression and Crushing Properties of a Straw-Lime Material

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.

Microstructural and Mechanical Properties of Al-Based Composites Reinforced with In-Situ and Ex-Situ Al2O3Nanoparticles

2015 ◽  
Vol 18 (4) ◽  
pp. 550-558 ◽  
Author(s):  
Riccardo Casati ◽  
Alberto Fabrizi ◽  
Giulio Timelli ◽  
Ausonio Tuissi ◽  
Maurizio Vedani
Keyword(s):  
Mechanical Properties ◽  
Ex Situ

Characterization of Dissimilar Welded Joints Between Austenitic and Duplex Stainless Steel Grades for Liquid Tank Applications

2018 ◽  
Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Welded Joints ◽  
Industrial Applications ◽  
Duplex Stainless Steels ◽  
Steel Pipes ◽  
Steel Grades ◽  
Welding Processes

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.

Fatigue of As-Fabricated Open Cell Aluminum Foams

2005 ◽  
Vol 127 (1) ◽  
pp. 40-45 ◽  
Author(s):  
J. Zhou ◽  
Z. Gao ◽  
A. M. Cuitino ◽  
W. O. Soboyejo
Keyword(s):  
Shear Bands ◽  
Digital Camera ◽  
Image Correlation ◽  
Ex Situ ◽  
Aluminum Foams ◽  
Open Cell ◽  
Strain Jump ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

This paper presents the results of the combined experimental investigation and digital image correlation (DIC) analysis of the fatigue failure of open cell aluminum foams. Compression–compression cyclic loads were applied to foam specimens under the as-fabricated condition. Following characterization of the S-N curve behavior, the macroscale deformation of the tested foam under fatigue was recorded using an in-situ digital camera. The deformation sequence was then analyzed using DIC technique. It was found that foams failed with an abrupt strain jump when shear bands were formed, and serious deformation up to more than 30% was developed in the center of the shear band. The ex-situ scanning electron microscopy analysis indicated that the abrupt strain jump was due to the microscale damage accumulation in struts where surface cracks were formed and propagated.

Correlation between the Enhanced Plasticity of Glassy Matrix Composites and the Volume Fraction, Size and Intrinsic Mechanical Property of Reinforcements

2014 ◽  
Vol 783-786 ◽  
pp. 1967-1970
Author(s):  
Z.H. Chu ◽  
Hidemi Kato ◽  
Guo Qiang Xie ◽  
D.R. Yan ◽  
Guang Yin Yuan
Keyword(s):  
Mechanical Properties ◽  
Metallic Glasses ◽  
Volume Fraction ◽  
Shear Bands ◽  
Ex Situ ◽  
Glassy Matrix ◽  
Matrix Composites ◽  
Micro Scale ◽  
Fraction Size

In recent years, bulk metallic glasses (BMGs) have received considerable attention due to their unique mechanical properties. However, the deformation of BMGs is highly localized in a few shear bands so that many of them exhibit poor plasticity. As such, more and more researchers have focused on improving the plasticity by in-situ or ex-situ introducing of nanoor micro-scale crystalline phases into the metallic glassy matrix in order to formation of multiple shear bands.

scholarly journals Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet

2009 ◽  
Vol 6 (40) ◽  
pp. 1097-1102 ◽  
Author(s):  
Kantesh Balani ◽  
Flavia C. Brito ◽  
Lidia Kos ◽  
Arvind Agarwal
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Tricuspid Valve ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Current Work ◽  
Valve Leaflet ◽  
Stiffness Measurement ◽  
Proper Functioning

Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7–10 GPa) than non-pigmented areas (2.5–4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism.

Fabrication of Aluminum/Aluminum Nitride Composites by Reactive Mechanical Alloying

2007 ◽  
Vol 534-536 ◽  
pp. 181-184
Author(s):  
Seung Hoon Yu ◽  
Kwang Seon Shin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Elevated Temperatures ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Processing Technique ◽  
Compression Tests ◽  
Composite Powders ◽  
Al Matrix Composites

Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above 600oC. The hot extrusion process was utilized to consolidate the composite powders. The composite powders were canned in an Al can and then extruded at elevated temperatures. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

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