Use of Hollomon equation in combination with conventional equation, for finding change in strain hardening exponent value, among differently aged and tensile tested maraging steel samples

Anomaly of the Work Hardening of Zn-Cu Single Crystals Oriented for Slip in Secondary SystemsThe copper alloyed (up to 1.5%) zinc single crystals oriented for slip in non-basal systems (orientation close to < 1120 >) were subjected to compression test within a range of temperatures of 77-293K. It has been stated, that Zn-Cu crystals exhibit characteristic anomalies of the thermal dependence of yield stress and of the strain hardening exponent. Both of them are related to the change in type and sequence of active non-basal slip systems: pyramidal of the 1storder {1011} < 1123 > (Py-1) and pyramidal of the 2ndorder {1122} < 1123 > (Py-2). The temperature anomaly of the yield stress results from the change of the slip from Py-2 systems to simultaneous slip in the Py-2 and Py-1 (Py-2 + Py-1) systems, occurring in the preyielding stage. On the other hand, sequential activation of pyramidal systems taking place in advanced plastic stage (i.e. the first Py-2 and next Py-2 + Py-1 systems) is responsible for temperature anomaly of strain hardening exponent. Increase in copper addition favors the activity of Py-2 systems at the expense of Py-1 slip, what leads to a drastic differences in plastic behavior of zinc single crystals.

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Closed form solutions of the differential equations governing the plastic fracture field in a power-law hardening material with low strain-hardening exponent

Ingenieur-Archiv ◽

10.1007/bf00531255 ◽

1990 ◽

Vol 60 (7) ◽

pp. 444-462 ◽

Cited By ~ 3

Author(s):

D. E. Panayotounakos ◽

M. Markakis

Keyword(s):

Differential Equations ◽

Closed Form ◽

Strain Hardening ◽

Power Law ◽

Strain Hardening Exponent ◽

Hardening Material ◽

Closed Form Solutions

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Influencing Factors for Improving Accuracy in Prediction of Stress Corrosion Crack Growth Rate in Boiling Water Reactor Operational Condition: Part 1—Prediction of SCC Growth Rate in Terms of Vickers Hardness

ASME 2010 Pressure Vessels and Piping Conference: Volume 1 ◽

10.1115/pvp2010-26135 ◽

2010 ◽

Author(s):

Yoichi Takeda ◽

Zhanpeng Lu ◽

Takeshi Adachi ◽

Qunjia Peng ◽

Jiro Kuniya ◽

...

Keyword(s):

Growth Rate ◽

Stainless Steel ◽

Yield Strength ◽

Strain Hardening ◽

Crack Growth ◽

Vickers Hardness ◽

316L Stainless Steel ◽

Strain Hardening Exponent ◽

Theoretical Formulation ◽

Prediction Curve

It is known that stress corrosion cracking (SCC) found in the operational power plants show complex cracking behaviors and it’s resulted in complex crack shape e.g. crack branching and its uneven crack front. For the cracking near the weldment, this is due to crack penetrated along the complex distribution of residual stress and strain hardened area. In this investigation, in order to advance the accuracy for crack growth prediction with considering such complex fields, theoretical formulation for SCC growth was further modified. Hardness of the materials, which is a measureable parameter even in operational power plant, was focused on to reflect strain hardening of the component like heat affected zone of the weldments. The theoretical formulation for SCC growth has terms with yield strength of the material and strain hardening exponent to describe crack tip strain rate. Strain hardening was simulated by cross rolling with the range of 4 – 32% as thickness reduction. Correlation between yield strength, strain hardening exponent at 288°C and Vickers hardness was obtained by means of tensile tests and hardness tests on 316L stainless steel. It was observed that a monotonic increase in Vickers hardness and yield strength with degree of reduction in thickness worked by cross rolling. Relationship between Vickers hardness and yield strength was found to have linear correlation. Further confirmation was made by plotting the reported mechanical properties data in terms of Vickers hardness. In addition, linear relationship was found between yield strength and strain hardening exponent. These relationships were introduced into SCC theoretical formulation and a SCC growth rate prediction curve in terms of Vickers hardness was proposed. SCC crack growth evaluation tests with selected work hardened 316L stainless steel were performed in oxygenated pure water environment at 288°C to confirm the predictability of the formulation. The prediction curve had a good agreement with available literature data as well as obtained crack growth rates in the hardness range of 140–300HV which was likely expected one in weld HAZ.

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THE ABILITY TO CLINCHING AS A FUNCTION OF MATERIAL HARDENING BEHAVIOR

Acta Metallurgica Slovaca ◽

10.12776/ams.v24i1.940 ◽

2018 ◽

Vol 24 (1) ◽

pp. 58

Author(s):

Tadeusz Balawender

Keyword(s):

Strain Hardening ◽

Strength Properties ◽

Strain Hardening Exponent ◽

Special Importance ◽

Metallic Materials ◽

Forming Process ◽

Plastic Properties ◽

Plastic Materials ◽

Mechanical Clinching ◽

Induced Defects

Mechanical clinching can be used to joining different metallic materials. The only restriction are their plastic properties. However some plastic materials, with good ductility, do not conform strong clinch joint, e.g. materials, featured by high strain hardening phenomena are difficult to clinching and do not create durable clinch joint. In case of others materials with limited ductility clinch forming generates the process-induced defects such as cracks. So, there are material’s features which are very important for the clinch forming process and among them the strain hardening properties seem to be in special importance. The clinch joints of different materials with diversified plastic and strength properties were tested. A single overlap clinch joints with one clinch bulge were realized in the tests. The joints were tested in the pull test. The obtained results showed the relation of the clinch joinability to the materials’ strain hardening exponent. The good quality and good strength joints, were obtained for materials with low value of strain hardening exponent below n = 0,22.

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Quasi-static compression behavior and microstructure changes in low-cost AA6061 composites

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211055339 ◽

2021 ◽

pp. 095440622110553

Author(s):

Hariharasakthisudhan P ◽

Hariharasudhan T ◽

Karthik S ◽

Sathickbasha K ◽

Surya Rajan B

Keyword(s):

Aspect Ratio ◽

Strain Hardening ◽

Axial Strain ◽

Low Cost ◽

Research Work ◽

Strain Hardening Exponent ◽

Static Compression ◽

Compression Behavior ◽

Maximum Value ◽

Quasi Static Compression

The workability study of the composites enhances the understanding of the degree of plastic deformation that can be employed on it. The current research work highlights the response of the low-cost aluminum composites reinforced with exhausted alkaline battery powders under quasi-static compression. The effect of reinforcements and aspect ratio against the strain hardening exponent and strength coefficients were investigated. The microstructural changes after quasi-static compression were studied and related to the changes in the property of the composites. The composite with 6 wt.% of reinforcement showed the least amount of porosity as 1.2%. In most of the cases, the maximum value of average strain hardening exponent with respect to axial strain was noted in the composites with 6 wt. % of reinforcement. The lowest aspect ratio of 0.5 showed the maximum workability in the composites. The average strength coefficient was found to be maximum (308.58 MPa) in the composite with 2 wt.% reinforcement. The elongated grains and slip bands were observed in the microstructure of the compressed specimens.

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Strain Hardening Exponent

Van Nostrand's Scientific Encyclopedia ◽

10.1002/0471743984.vse6774 ◽

2005 ◽

Keyword(s):

Strain Hardening ◽

Strain Hardening Exponent

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Anisotropy Study of Inconel 718 alloy at Sub-Zero temperatures

E3S Web of Conferences ◽

10.1051/e3sconf/202018401004 ◽

2020 ◽

Vol 184 ◽

pp. 01004

Author(s):

L Jayahari ◽

K Nagachary ◽

Chandra Ch Sharath ◽

SM Hussaini

Keyword(s):

Mechanical Properties ◽

Strain Hardening ◽

Inconel 718 ◽

Anisotropy Parameter ◽

Tensile Tests ◽

Strain Hardening Exponent ◽

Inconel 718 Alloy ◽

Normal Anisotropy ◽

Axial Tensile ◽

Forming Characteristics

There is an increase in demand for new alloys in aerospace, power generation and nuclear industries. Nickel Based super alloys are known for having distinctive properties which are best suitable for these industries. In this study Nickel based super alloy Inconel 718, is used. Over the many years of intense research and development, these alloys have seen considerable evolution in their properties and efficiency. Behaviour of materials and its forming characteristics can be precisely analysed by determining anisotropic behaviour and mechanical properties. In the present study, tried to analyse the mechanical properties of Inconel 718 like yield strength (Ys), ultimate tensile strength (UTS), strain hardening exponent (n) and strain hardening coefficient (k). Uni-axial tensile tests were conducted on specimens with various parameters such as orientations, temperature and Strain rate. Anisotropy of Inconel 718 alloy was measured based on measurable parameters. The normal anisotropy parameter (f) and planer anisotropy (Δr) were measured and observed that the anisotropy parametres are incresed with the decrease in temperature.

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