Mechanical characterization of secondary-hardening martensitic steel using nanoindentation

2004 ◽  
Vol 19 (1) ◽  
pp. 79-84 ◽  
Author(s):  
T. Ohmura ◽  
T. Hara ◽  
K. Tsuzaki ◽  
H. Nakatsu ◽  
Y. Tamura
Keyword(s):  
High Purity ◽  
Retained Austenite ◽  
Precipitation Hardening ◽  
Mechanical Characterization ◽  
Martensitic Steel ◽  
Secondary Hardening ◽  
Softening Behavior ◽  
Matrix Strength ◽  
The Matrix

Mechanical characterizations using nanoindentation technique were performed for the martensitic steel used as practical dies steel containing carbide-former elements of Cr, Mo, W, and V, which are responsible for secondary hardening by tempering. The nanohardnessHncorresponding to the matrix strength shows obvious secondary hardening, and the hardening-peak temperature coincides with that of the macroscale hardnessHv. By comparing the temper-softening behavior of the high-purity Fe–C binary martensite, the ratio of the nanohardnessHnof the dies steel to that of the Fe–C binary steel is approximately a factor of two, whereas the same ratio of the macroscopic hardnessHvis three at the secondary-hardening peak. These results suggest that the secondary hardening of the dies steel during tempering is attributed not only to the nanoscale strengthening factors such as precipitation hardening by the alloy carbides, but also to some other factors in larger scale. One of the strengthening factors in larger scale is a decomposition of 9% retained austenite to much harder phases, such as martensite and/or ferrite–cementite constituent.

Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

2021 ◽  
pp. 002199832110055
Author(s):  
Zeeshan Ahmad ◽  
Sabah Khan
Keyword(s):  
Tensile Strength ◽  
Boron Carbide ◽  
Mechanical Characterization ◽  
Stir Casting ◽  
Surface Mapping ◽  
Alloy Matrix ◽  
Casting Technique ◽  
The Matrix ◽  
Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

Physical and mechanical characterization of nanocomposites with carbon nanotubes functionalized with the matrix polymer

2005 ◽  
Vol 12 (8-9) ◽  
pp. 757-768 ◽  
Author(s):  
M. C. Paiva ◽  
B. Zhou ◽  
K. A. S. Fernando ◽  
Y. Lin ◽  
P. E. Lopes ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Characterization ◽  
Matrix Polymer ◽  
The Matrix

scholarly journals Mechanical Characterization of FRBC prepared from Coir Fibres

2019 ◽  
Vol 9 (2) ◽  
pp. 3802-3805
Keyword(s):  
Tensile Strength ◽  
Mechanical Characterization ◽  
Flexural Rigidity ◽  
Orientation Angle ◽  
Coir Fiber ◽  
Light Weight ◽  
Test Results ◽  
The Matrix ◽  
Epoxy Material

This experimental study demonstrates the consequences of orientation of fibers in fibre reinforced biocomposite materials (FRBC) and its impact on their mechanical behaviour. Various samples of FRBC were synthesized from coir rope using hand layup method and epoxy resin in which orientation of coir rope was varied at 0°, 45° and 90° respectively. Test results reveal enhancements in tensile strength while reduction in flexural rigidity for all the samples of prepared composite in comparison to samples of pure epoxy material. The mechanical behavior of FRBCs is sensitive to the orientation angle of coir fiber in the matrix. The results show improved tensile strength for FE-90 samples by about 28%, but the flexural rigidity declined by about 59% as compared to E-samples. The minimum decline in flexural rigidity is about 16% for FE-00 samples while tensile strength enhanced by about 11% approx. It is concluded that, FRBCs prepared from coir fibres with hand layup method, are light weight and possess improved strength therefore, they are suitable for structural and reinforcement purpose.

An Alternative Approach for FRCM Matrix Tensile Strength Evaluation

2019 ◽  
Vol 817 ◽  
pp. 365-370 ◽  
Author(s):  
Alessandro Bellini ◽  
Marco Bovo ◽  
Andrea Incerti ◽  
Claudio Mazzotti
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Mechanical Characterization ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Test Methods ◽  
Test Method ◽  
The Matrix ◽  
Flexural Tests

Structural retrofitting with composite materials proved to be an effective technique for rehabilitation of degraded or damaged masonry and concrete buildings. Nowadays, Fiber Reinforced Cementitious Matrix (FRCM) composites are widely used as externally bonded strengthening systems thanks to their high performance, low weight and easiness of installation. Several experimental tests and numerical studies are currently available concerning the tensile and bond behavior of FRCM systems, but a debated and still open issue concerns the methods for the mechanical characterization of the mortar used as matrix within the strengthening system. The present paper analyses and compares different test methods for determining the matrix tensile strength. Pure tensile and flexural tests have been carried out on different mortar matrix samples. In order to evaluate which is the most suitable value to be considered for a correct interpretation and modeling of the composite system, the experimental results obtained through flexural tests on standard mortar specimens have been compared with the outcomes obtained from direct tensile tests on FRCM coupons. The present study represents only a first step for the definition of the most appropriate test method for the mechanical characterization of the matrix used within FRCM strengthening systems.

scholarly journals ENGINEERING GEOLOGICAL BEHAVIOUR OF HETEROGENEOUS AND CHAOTIC ROCK MASSES

2017 ◽  
Vol 43 (1) ◽  
pp. 183 ◽  
Author(s):  
G. Tsiambaos
Keyword(s):  
Rock Mass ◽  
Mechanical Behaviour ◽  
Mechanical Characteristics ◽  
Rock Masses ◽  
Rock Mass Strength ◽  
Matrix Strength ◽  
The Matrix ◽  
Scientists And Engineers ◽  
Geological Formations

The engineering characterization of heterogeneous and complex geological formations for estimating their rock mass strength and deformability characteristics constitutes a challenge to geo-scientists and engineers dealing with the design and construction of slopes and tunnels. Mélanges and similar heterogeneous mixtures of hard blocks in weaker matrix, known as “bimrocks”, present an overall strength significantly greater than the matrix strength, because the presence of rock blocks, above a threshold volumetric proportion, influences the mechanical characteristics and the behaviour of these rock masses. Moreover, recent studies have shown that the strength and mechanical behaviour of heterogeneous and composite rock masses such as flysch and molasses consisting of alternating layers of competent and incompetent rocks are governed by the presence and volumetric percentage of the interlayers of the weaker rocks.

Characterization of Polycarbonate/Multiwalled Carbon Nanotube Composites

2006 ◽  
Vol 326-328 ◽  
pp. 1829-1832 ◽  
Author(s):  
Hun Sik Kim ◽  
Byung Hyun Park ◽  
Min Sung Kang ◽  
Jin San Yoon ◽  
Hyoung Joon Jin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Multiwalled Carbon ◽  
Melt Compounding ◽  
Matrix Strength ◽  
The Matrix ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Scanning Electron

Polycarbonate/multiwalled carbon nanotubes (PC/MWNT) nanocomposites with different contents of MWNT were successfully prepared by melt compounding. The mechanical properties of the PC/MWNT nanocomposites were effectively increased due to the incorporation of MWNTs. The composites were characterized using scanning electron microscopy in order to obtain the information on the dispersion of MWNT in the polymeric matrix. In case of 0.3 wt% of MWNT in the matrix, strength and modulus of the composite increased by 30% and 20%, respectively. In addition, the dispersion of MWNTs in the PC matrix resulted in substantial decrease in the electrical resistivity of the composites as the MWNTs loading was increased from 1.0 wt% to 1.5 wt%.

Mechanical Characterization of Polypropylene Natural Fibre Composites

2011 ◽  
Vol 383-390 ◽  
pp. 2737-2740 ◽  
Author(s):  
Sd Jacob Muthu ◽  
Ratnam Paskaramoorthy
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Fibre Surface ◽  
Alkaline Treatment ◽  
Natural Fibre ◽  
Fibre Composites ◽  
The Matrix ◽  
Pp Composites ◽  
Fibre Loading

Using polypropylene (PP) as matrix and kenaf mat as reinforcement, composite test samples were fabricated by compression molding. Thereafter, the effect of fibre loading and the alkaline fibre surface treatment on the mechanical properties were studied. The kenaf/PP composites were found to have better mechanical properties than the polymer matrix. As expected, the interfacial bonding between the matrix and the fibres improved considerably when the fibres were subjected to alkaline treatment.

Small-scale structural and mechanical characterization of the nitrided layer in martensitic steel

2013 ◽  
Vol 61 ◽  
pp. 109-115 ◽  
Author(s):  
Masoud Asgari ◽  
Afrooz Barnoush ◽  
Roy Johnsen ◽  
Rune Hoel
Keyword(s):  
Mechanical Characterization ◽  
Martensitic Steel ◽  
Nitrided Layer ◽  
Small Scale

Mechanical characterization of the softening behavior of human vaginal tissue

2011 ◽  
Vol 4 (3) ◽  
pp. 275-283 ◽  
Author(s):  
E. Peña ◽  
P. Martins ◽  
T. Mascarenhas ◽  
R.M. Natal Jorge ◽  
A. Ferreira ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Vaginal Tissue ◽  
Softening Behavior

Biaxial Mechanical Characterization of Bat Wing Skin and Development of Biomimetic Constructs

2013 ◽  
Author(s):  
A. J. Skulborstad ◽  
N. C. Goulbourne
Keyword(s):  
Mechanical Characterization ◽  
Tissue Structure ◽  
Fiber Architecture ◽  
Fiber Reinforced Materials ◽  
The Matrix ◽  
Wing Skin ◽  
Bat Wing ◽  
Structure Properties

The highly flexible and extensible wing skin of bats enables various wing shapes and flight modes, which distinguishes it from all other natural flyers making bats an ideal model for micro-aerial vehicles. We propose that an understanding of the relationship between the structure, properties and function of the wing tissue is essential to replicate and utilize the bat’s natural capabilities. In this work, we present the first biaxial mechanical characterization of bat wing skin, identify key mechanisms in its deformation, and employ these concepts to fabricate biomimetic skins. Ten Glossophaga soricina bat specimens were available for experiment obtained from Prof. Swartz or Brown University. Of the 20 excised wing skin samples, 11 were used for establishing testing protocols, 3 tore during preparation, and 6 were tested for the characterization presented in this work. The tissue was shown to be nonlinear, heterogeneous, anisotropic, and viscoelastic. The wrinkled tissue structure and substantial anisotropy promote great spanwise deployment and deformation increasing wing area and aspect ratio enabling greater lift generation. Comparison of the material structural organization with strain field responses demonstrated that the underlying fiber architecture corresponds to observed local strain variations and that the tissue represents a departure from traditional fiber reinforced materials since the mesoscopic elastin fiber architecture appears to be the soft component while the matrix provides the stiffening role. Fabricated skins capture the inherent mismatch in natural configurations of the spanwise elastin fibers and the matrix and exhibit the characteristic wrinkle pattern observed in the in vivo bat wing skin. Future work will include static mechanical testing of the synthetic skins as well as aerodynamic testing to investigate the link between tissue structure, properties and functional flight capabilities.

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