Elastic Recovery and Plastic Flow in Raw Rubber

1940 ◽  
Vol 13 (4) ◽  
pp. 795-806 ◽  
Author(s):  
L. R. G. Treloar
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Plastic Flow ◽  
Elastic Strain ◽  
Elastic Recovery ◽  
Complete Removal ◽  
Low Energy ◽  
Great Care ◽  
Different Temperatures

Abstract In considering existing information on the mechanical properties of raw rubber, it is not generally possible to distinguish between the effects of elastic and of plastic deformation. In the experiments described great care was taken to secure the complete removal of elastic strain, after stretching to various extensions at different temperatures. The plastic flow increased to a maximum with increasing elongation and fell again at higher elongations, an effect attributed to the increase of crystallization with increasing extension. For rubber held extended for one hour at 25° C the flow was never greater than 2% of the original extension, and for extensions greater than 440% or less than 130% it was negligibly small. Curves showing the decay of tension at constant extension, and the recovery of length after stretching, in conjunction with the observations on plastic flow, are interpreted in terms of a theory proposed by Busse, according to which the rubber molecules are held together at certain points by cohesional linkages of low energy, some of which are broken down during stretching.

Severe Plastic Deformation of Amorphous Alloys

2008 ◽  
Vol 584-586 ◽  
pp. 227-230 ◽  
Author(s):  
Alex M. Glezer ◽  
Sergey V. Dobatkin ◽  
Margarita R. Plotnikova ◽  
Anna V. Shalimova
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Amorphous Alloy ◽  
Severe Plastic Deformation ◽  
Physical Properties ◽  
Plastic Flow ◽  
Low Temperatures ◽  
Amorphous Alloys ◽  
Thermally Activated ◽  
Different Temperatures

The structure and mechanical properties of amorphous alloy Ni44Fe29Co15Si2B10 after severe plastic deformation (SPD) in Bridgman chamber at the different temperatures (77 and 298 K) have been studied. It is shown that the early stages of the SPD of amorphous alloy cause a noticeable decrease in microhardness HV and significant changes in the physical properties. With increasing the value of SPD the transition from inhomogeneous to homogeneous (or to qualitatively different) mode of plastic flow is observed, which is accompanied by the effects of homogeneous nanocrystallization. The nanoparticle size does not exceed 10 nm. It is established that the thermally activated nanocrystallization processes can occur at very low temperatures (77 K).

scholarly journals Effect of Hydrogen Content and Bonding Environment on Mechanical Properties of Hydrogenated Silicon Films Deposited by High-Frequency PECVD Process

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Jhuma Gope ◽  
Sushil Kumar ◽  
A. Parashar ◽  
S. Dayal ◽  
C. M. S. Rauthan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Hydrogen Content ◽  
High Frequency ◽  
Laser Scanning ◽  
Elastic Recovery ◽  
Deformation Energy ◽  
Intrinsic Stress ◽  
Ir Absorption ◽  
Hydrogenated Silicon

The mechanical properties of hydrogenated silicon thin films deposited using high-frequency PECVD process were studied, which certainly have importance for optoelectronic devices particularly for getting stability and long operating lifetime in harsh conditions. Nanoindentation technique was used to measure the load versus displacement curves, hardness (H), elastic modulus (E), plastic resistance parameter (H/E), elastic recovery (ER), and plastic deformation energy (Ur), while laser scanning stress measurement setup was used to measure the intrinsic stress of these films. The concentration of bonded hydrogen in these films was found in the range of 3.6 to 6.5 at. % which was estimated using integrated intensity of IR absorption peak near 640 cm−1. Dependence of mechanical properties of these films on hydrogen content and bonding environment has been investigated. The film containing minimum hydrogen content (3.6%) shows the maximum elastic recovery (52.76%) and minimum plastic deformation energy (3.95×10−10 J). Surface roughness measured by AFM was found to decrease with the increase in hydrogen content in the film. The dependency of stress on the plasma frequency and applied power has also been discussed.

The Yield Condition and Flow Rule for a Metal Subjected to Finite Elastic Volume Change

1971 ◽  
Vol 93 (4) ◽  
pp. 708-712 ◽  
Author(s):  
J. B. Haddow ◽  
T. M. Hrudey
Keyword(s):  
Plastic Deformation ◽  
Hydrostatic Pressure ◽  
Plastic Flow ◽  
Volume Change ◽  
High Hydrostatic Pressure ◽  
Elastic Strain ◽  
Yield Condition ◽  
Flow Rule ◽  
Elastic Plastic ◽  
Plastic Flow Rule

A theory for elastic-plastic deformation with finite elastic strain is outlined. The results of this theory are specialized to consider a metal subjected to high hydrostatic pressure which produces finite elastic volume change. Drucker’s postulate is used to obtain the form of the yield condition and the associated plastic flow rule.

The Effect of the Glass-Transition Temperature of Conventional and Radiation-Deposited Polymeric Additives on Mechanical Properties of Cotton Fabric

1969 ◽  
Vol 39 (12) ◽  
pp. 1126-1134 ◽  
Author(s):  
W. K. Walsh ◽  
M. A. Siahkolah ◽  
Henry A. Rutherford
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Cotton Fabric ◽  
Elastic Recovery ◽  
Cross Linking ◽  
Surface Deposition ◽  
Polymeric Additives ◽  
Different Temperatures ◽  
Radiation Induced ◽  
Recovery Angle

The change in properties of cotton fabric produced by polymeric additives with varying degrees of stiffness or softness has been investigated by measuring these properties at different temperatures. It was concluded that changes in crease-recovery angle produced by these polymers were not due to lubrication but were related to the elastic-recovery properties of the added polymer. Changes in tear strength and abrasion resistance were shown to be a function of interyarn mobility by measuring yarn withdrawal forces of the fabrics. Radiation-induced deposition of polymers produced changes that were qualitatively similar to those made by conventional polymer applications, but the changes were not as pronounced. This was attributed to the lower degree of surface deposition and the lack of cross-linking of the radiation deposited polymers.

Analysis of Plastic Properties of Fe-Based Coatings at Different Annealing Temperatures by Nanoindentation

2019 ◽  
Vol 807 ◽  
pp. 121-127
Author(s):  
Zhe Yu ◽  
Hao Yue Yang ◽  
Zi Kun Song ◽  
Sui Xuan Lin ◽  
Hua Yi Li
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Penetration Depth ◽  
Elastic Recovery ◽  
Strain Hardening Exponent ◽  
Stress Strain ◽  
Plastic Properties ◽  
Different Temperatures ◽  
Critical Yield ◽  
1045 Steel

Fe-based alloys were deposited on 1045 steel by plasma cladding technique and the specimens were annealed at different temperatures. Instrumented indentation technique was adopted to investigate the plastic properties of the coatings, especially the stress-strain relations, critical yield stress and the strain hardening exponent. The results show that the elastic recovery in nanoindentation is less than 20% for all coatings and proves an obvious existence of plastic deformation in the coatings. It is found in the stress-strain curves that the annealing process makes the distribution of elastic modulus among the whole coating more uniformly. With the penetration depth increasing, the initial plastic deformation value gradually decreased which is more obvious for coatings annealing at high temperatures. In addition, the strain hardening exponent of the as-cladding coating and coatings annealed at 500°C keeps steady around 0.15 while the corresponding values of coatings annealed at 600°C and 700°C increased sharply with the penetration depth increasing and the maximum value is up to 0.32.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 13. DETERMINATION OF DEFORMED STATE UNDER STRAITENED EXTRUSION IN FOURTH CENTRAL AREA OF PLASTIC DEFORMATION

2020 ◽  
Vol 0 (4) ◽  
pp. 43-51
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Central Area ◽  
Direct Extrusion ◽  
Deformed State ◽  
Cumulative Deformation ◽  
The Given ◽  
General Method

Formulae have been obtained that are necessary to calculate cumulative deformation in the process of straitened extrusion in the central area closed to the working end of the counterpunch. The general method of plastic flow proposed by A. L. Vorontsov was used. The obtained formulae allow one to determine the deformed state of a billet in any point of the given area. The formulae should be used to take into account the strengthening of the extruded material.

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