Room Temperature Tensile Ductility in Polycrystalline B2 NiAl

1988 ◽  
Vol 133 ◽  
Author(s):  
K. Vedula ◽  
K. H. Hahn ◽  
B. Boulogne
Keyword(s):  
Yield Strength ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Tensile Ductility ◽  
Lower Yield ◽  
Polycrystalline Alloys ◽  
Lower Yield Strength ◽  
Stoichiometric Alloy

ABSTRACTBinary polycrystalline alloys of B2 NiAl, ranging from 47 to 51.5 at% Al, were prepared by casting and extrusion. These were tested in tension at temperatures ranging from 300 K to 873 K. Significant tensile ductility is observed in the near-stoichiometric alloy at room temperature as well as at 473 K in spite of the presence of only <100> dislocations. This anomaly appears to be related to the recrystallized texture, to the lower yield strength and to the presence of residual dislocations at grain boundaries in this alloy.

Room Temperature Tensile Ductility in Powder Processed B2 FeAi Alloys

1986 ◽  
Vol 81 ◽  
Author(s):  
M. A. Crimp ◽  
K. M. Vedula ◽  
D. J. Gaydosh
Keyword(s):  
Fracture Surface ◽  
Yield Strength ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Cooling Rate ◽  
Yield Stress ◽  
Room Temperature ◽  
Tensile Ductility ◽  
Strengthening Mechanism ◽  
General Yielding

AbstractIt has been shown that it is possible to obtain significant room temperature tensile ductility in FeAl alloys using iron-rich deviations from stoichiometry. A comparison of the room temperature tensile and compressive behaviors of Fe−50at% Al and Fe−40at% Al shows that FeAl is brittle at higher Al contents because it fractures along grain boundaries before general yielding. Lower aluminium contents reduce the yield stress substantially and hence some ductility is observed before fracture.Addition of boron results in measurable improvements in ductility of Fe−40at% Al and is accompanied by an increase in transgranular tearing on the fracture surface, suggesting a grain boundary strengthening mechanism.Increasing the cooling rate following annealing at 1273 K results in a large increase in the yield strength and a corresponding decrease in ductility.

An Investigation of Adaptive Rubber Bearings

2016 ◽  
Author(s):  
C. S. Tsai ◽  
Hui-Chen Su ◽  
Wen-Chun Huang
Keyword(s):  
Yield Strength ◽  
Lower Yield ◽  
Passive Devices ◽  
Major Benefit ◽  
Lead Rubber Bearings ◽  
Lower Yield Strength ◽  
Multiple Levels ◽  
Materials Used ◽  
Rubber Bearings ◽  
Stiffness And Damping

Proposed in this study are several innovative seismic isolators composed of rubber materials that are called adaptive rubber bearings based on their adaptive characteristics. The materials used in the proposed isolators are free of lead commonly found in lead rubber bearings. The lead material results in a heavy environmental burden as well as lower yield strength and damping due to rising temperature during earthquakes, and thus causes larger displacements than we would expect. The designed mechanisms in the proposed isolators enable these devices to be manufactured relatively easily. They also provide extremely high damping to bearings, which is strongly desired by engineers in practice. The proposed rubber bearings are completely passive devices yet possess adaptive stiffness and adaptive high damping. The change in stiffness and damping is predictable and can be calculated at specifiable and controllable displacement amplitudes. The major benefit of the adaptive characteristics of seismic isolators is that a given system can be optimized separately for multiple performance objects at multiple levels of earthquakes. In this study, mathematical formulations are derived to explain the mechanisms of the proposed devices. Experimental results of high velocity cyclical loadings are also provided to verify the advanced concepts of the proposed devices.

Mechanical Properties and Morphologies of PP/Co-PP/Talc Composites for Microwave Application

2012 ◽  
Vol 626 ◽  
pp. 711-715 ◽  
Author(s):  
J. Piwsawang ◽  
T. Jinkarn ◽  
Chiravoot Pechyen
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Filler Loading ◽  
Lower Yield ◽  
Elongation At Break ◽  
Compression Load ◽  
Microwave Application ◽  
Lower Yield Strength ◽  
Morphology Development ◽  
Internal Mixer

Unmodified talc fillers were compounded with polypropylene (PP) and copolymer polyethylene (Co-PP) separately in a Brabender plasticorder internal mixer at 180 °C and 50 rpm in order to obtain composites, which contain 040 phr (per 100 part of resin) of filler at 40 phr intervals. The morphology development and the mechanical properties of the composites with reference to filler loading were investigated. In terms of mechanical properties, Youngs modulus and maximum compression load increased, whereas yield strength and elongation at break decreased with the increase in filler loading of PP/Co-PP/Talc composites. The PP/Co-PP exhibited lower yield strength and youngs modulus, and higher elongation at break than talc composites (data not show here). Scanning electron microscopy (SEM) was used to examine the structure of the fracture surface to justify the variation of the measured mechanical properties.

A work-hardening model of the lower yield strength of discontinuously yielding alloys: Ni3Al and mild steel

1989 ◽  
Vol 4 (3) ◽  
pp. 470-472 ◽  
Author(s):  
E. M. Schulson
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Mild Steel ◽  
Work Hardening ◽  
Lower Yield ◽  
Hardening Model ◽  
Lower Yield Strength ◽  
Work Hardening Model ◽  
Lüders Bands

The lower yield strengths of Ni3Al and mild steel and their respective relationships to (grain size)−0.8 and (grain size)−0.5 are explained in terms of work hardening within Lüders bands.

scholarly journals Experimental study of zone of yield strength on corroded construction steel specimens for reuse

2019 ◽  
Vol 279 ◽  
pp. 02009
Author(s):  
Antonio Shopov ◽  
Borislav Bonev
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Experimental Study ◽  
Yield Strength ◽  
Structural Changes ◽  
Steel Structures ◽  
Strain Diagram ◽  
Lower Yield ◽  
Structural Element ◽  
Lower Yield Strength

Zone of yield strength is a part of stress-strain diagram on steel. In this zone is located an upper and lower yield strength points. These points are important for calculation and design of steel structures elements. When a structural element is corroded, its mechanical properties are changed i.e. changes the geometric characteristics, superficial defects appear and leads to structural changes of material. The facts unambiguously determine that in order to decide whether or not the corrosion element can be reuse, it is necessary to study the material and to determine the new values at the yield strength points. In order to legally make the necessary calculation in sizing and to judge for its reuse. The report studies a zone of yield strength on steel elements with corrosion. Experimental data was obtained, then processed using the stochastic method of processing empirically obtained data, and it was determined with sufficient probability the values to be used for calculation and design in practice.

Influence of Inhomogeneous Deformation on Tensile Behavior of Sheets Processed Through Constrained Groove Pressing

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Sunil Kumar ◽  
S. Venkatachalam ◽  
Hariharan Krishnaswamy ◽  
Ravi Kumar Digavalli ◽  
H. S. N. Murthy
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Strain Distribution ◽  
Fe Simulation ◽  
Total Elongation ◽  
Image Correlation ◽  
Lower Yield ◽  
Standard Specimens ◽  
Lower Yield Strength ◽  
Miniature Specimens

Constrained groove pressing (CGP) is a severe plastic deformation technique to produce the ultra-fine grained sheet. The inhomogeneous strain distribution and geometry variation induce differential mechanical properties in the processed sheet. The improved mechanical properties of CGP sheets is due to the composite effect of weak and strong regions formed by geometric and strain inhomogeneities. Weaker regions exhibit large strain, lower yield strength, and higher strain hardening compared to stronger regions. The estimation of mechanical properties is influenced by these defects leading to the difference in the mechanical properties along different orientations. Experimental investigation revealed that the commonly used tensile samples cut perpendicular to the groove orientation exhibit variation in thickness along the gauge length affecting the results from tensile tests. To further understand the effect of geometric variation, a typical CGP specimen was reverse engineered and finite element (FE) simulation was performed using the actual geometry of the CGP processed specimen. The strain distribution from FE simulation was validated experimentally using the digital image correlation data. Based on the numerical and experimental studies, miniature specimens were designed to eliminate the geometric effects from the standard parallel specimen. Miniature parallel specimens showed lower yield strength and total elongation compared to the standard specimens. However, the statistical scatter of total elongation of the miniature specimens was much less than that of the standard specimens, indicating better repeatability. Probably this is the first study to quantify the contribution of composite geometric effect in the mechanical properties of CGP.

Effect of Forging Temperature on Microstructure and Tensile Properties in Fe3Al-Based Alloy

1994 ◽  
Vol 364 ◽  
Author(s):  
Y. Yang ◽  
W. Yan ◽  
J. N. Liu ◽  
S. Hanada
Keyword(s):  
Plastic Deformation ◽  
Low Temperature ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Different Temperatures ◽  
Local Plastic Deformation ◽  
Strength And Ductility

AbstractForging processes at two different temperatures are performed to examine the relation between the microstructure and room temperature tensile properties in a Ce doped Fe3Al-based alloy. Results show that the microstructure and the ductility are sensitive to the forging temperature before annealing treatment. Higher yield strength and ductility can be obtained through forging at a relatively low temperature of 750°C followed by annealing at 800°C and 500°C. It is suggested that the formation of non-equilibrium grain boundaries and banded subgrains within carbide-free areas along grain boundaries enhances the local plastic deformation and results in the improvement of ductility. During the initial deformation at room temperature <111> slip is predominant for both microstructures.

The Expansion Forming Parameters of the Expandable Tubular Material

2014 ◽  
Vol 1061-1062 ◽  
pp. 530-533
Author(s):  
Wen Zhu Shen ◽  
Yang Yang ◽  
Chun Fu Li ◽  
Wei Xiang Yang ◽  
Xing Jin
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Strain Hardening ◽  
Lower Yield ◽  
The Past ◽  
Forming Parameters ◽  
Lower Yield Strength ◽  
Great Development

Expandable tubing technology got great development in the past few years because of its extensive usages. Expandable material must has such properties as lower yield strength, higher tensile strength, better plasticity and strain hardening properties, and so on. This paper introduced some expansion forming parameters. These expansion forming parameters can be used to characterize the expansion properties.

scholarly journals Yield Load Solutions for SE(B) Fracture Toughness Specimen with I-Shaped Heterogeneous Weld

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 214
Author(s):  
Pejo Konjatić ◽  
Marko Katinić ◽  
Dražan Kozak ◽  
Nenad Gubeljak
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Fracture Behavior ◽  
Lower Yield ◽  
Yield Load ◽  
Weld Metals ◽  
Lower Yield Strength ◽  
Fracture Toughness Specimen ◽  
Good Agreement

The objective of this work was to investigate the fracture behavior of a heterogeneous I-shaped welded joint in the context of yield load solutions. The weld was divided into two equal parts, using the metal with the higher yield strength and the metal with the lower yield strength compared to base metal. For both configurations of the I-shaped weld, one with a crack in strength in the over-matched part of the weld and one for a crack in the under-matched part of the weld, a systematic study of fracture toughness SE(B) specimen was carried out in which the crack length, the width of the weld and the strength mismatch factor for both weld metals were varied, and the yield loads were determined. As a result of the study, two mathematical models for determination of yield loads are proposed. Both models were experimentally tested with one strength mismatch configuration, and the results showed good agreement and sufficiently conservative results compared to the experimental results.

Effect of hafnium addition on a Ni-Al-Co Alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 940-941
Author(s):  
L. S. Lin ◽  
G. W. Levan ◽  
S. M. Russell ◽  
C. C. Law
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Ternary Alloy ◽  
Room Temperature ◽  
Gamma Prime ◽  
Room Temperature Ductility ◽  
Appreciable Increase ◽  
Hf Addition

Recent efforts at P&W have shown that the addition of cobalt to binary NiAl results in an appreciable increase in room temperature ductility. One version of this ternary alloy, designated VIM A, has a composition of Ni-30 at.% Al-35 at.% Co. The addition of 0.5 at.% Hf to this alloy (designated VIM AH) results in an improvement in yield strength at 760°C. Room temperature properties were not found to be significantly affected by the Hf addition. This discussion will focus on the microstructures of alloys VIM A and VIM AH and their relationship to the mechanical properties observed in compression at room temperature and 760°C.The addition of hafnium reduced the grain size of VIM AH alloy. After room temperature compression, both alloys show an ordered bcc (B2) matrix and precipitates which are distributed primarily along grain boundaries. These precipitates were identified by microdiffraction to be ordered fcc (L12) gamma prime for VIM A and hexagonal (A3) for VIM AH.

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