On the anomalous work-hardening behaviour of polycrystalline metals at low temperatures

1984 ◽  
Vol 3 (7) ◽  
pp. 629-632 ◽  
Author(s):  
S. M. Raza ◽  
N. Z. Butt
Keyword(s):  
Work Hardening ◽  
Low Temperatures ◽  
Polycrystalline Metals

Internal friction and sound velocity of polycrystalline metals at very low temperatures

1994 ◽  
Vol 211-212 ◽  
pp. 27-32 ◽  
Author(s):  
Pablo Esquinazi ◽  
Reinhard König ◽  
Dieter Valentin ◽  
Frank Pobell
Keyword(s):  
Internal Friction ◽  
Sound Velocity ◽  
Low Temperatures ◽  
Polycrystalline Metals

Deformation Mechanisms in High-Al Bearing High-Mn TWIP Steels in Hot Compression and in Tension at Low Temperatures

2007 ◽  
Vol 550 ◽  
pp. 217-222 ◽  
Author(s):  
Atef S. Hamada ◽  
L. Pentti Karjalainen ◽  
Mahesh C. Somani ◽  
R.M. Ramadan
Keyword(s):  
Austenitic Steel ◽  
Work Hardening ◽  
Hot Deformation ◽  
Low Temperatures ◽  
Deformation Behaviour ◽  
Tensile Tests ◽  
Mechanical Twinning ◽  
Al Content ◽  
Duplex Steel ◽  
Twip Steels

The hot deformation behaviour of two high-Mn (23-24 wt-%) TWIP steels containing 6 and 8 wt-% Al with the fully austenitic and duplex microstructures, respectively, has been investigated at temperatures of 900-1100°C. In addition, tensile properties were determined over the temperature range from -80 to 100°C. It was observed that in spite of the lower Al content, the austenitic steel possessed the hot deformation resistance about twice as high as that of the duplex steel. Whereas the flow stress curves of the austenitic steel exhibited work hardening followed by slight softening due to dynamic recrystallisation, the duplex steel showed the absence of work hardening and discontinuous yielding under similar conditions. Tensile tests at low temperatures revealed that the austenitic grade had a lower yield strength than that of the duplex grade, but much better ductility, the elongation increasing with decreasing temperature, contrary to that for the duplex steel. This can be attributed to the intense mechanical twinning in the austenitic steel, while in the duplex steel, twinning occurred in the ferrite only and the austenite showed dislocation glide.

Staged work hardening of polycrystalline titanium at low temperatures and its relation to substructure evolution

2002 ◽  
Vol 28 (12) ◽  
pp. 935-941 ◽  
Author(s):  
V. A. Moskalenko ◽  
A. R. Smirnov ◽  
V. N. Kovaleva ◽  
V. D. Natsik
Keyword(s):  
Work Hardening ◽  
Low Temperatures

Microstructure-property hypermaps for shock-loaded materials

1986 ◽  
Vol 44 ◽  
pp. 416-419
Author(s):  
L. E. Murr
Keyword(s):  
Strain Hardening ◽  
Work Hardening ◽  
Residual Deformation ◽  
Dislocation Motion ◽  
Metals And Alloys ◽  
Crystal Defects ◽  
Deformation Mechanisms ◽  
Microstructural Changes ◽  
Polycrystalline Metals

Residual deformation-induced metallurgical effects or structure (microstructure)-property relationships are now generally well documented to be the result of stress or strain-induced microstructures, or microstructural changes in polycrystalline metals and alloys. In many cases, strain hardening, work hardening, or other controlling deformation mechanisms can be described by the generation, movement, and interactions of dislocations and other crystal defects which produce drag, or a range of impedances, including obstacles to dislocation motion.

The Mechanism of Work-hardening of Metals

1952 ◽  
Vol 166 (1) ◽  
pp. 413-418 ◽  
Author(s):  
N. F. Mott
Keyword(s):  
Work Hardening ◽  
Slip Line ◽  
Low Temperatures ◽  
Lattice Site ◽  
Dislocation Line ◽  
Slip Lines ◽  
Slip Bands ◽  
Cold Worked ◽  
Internal Strains ◽  
Full Height

The most striking feature of the deformation of metals is the formation of slip lines. Recent investigations suggest that, when formed at low temperatures, each slip line is the result of a displacement of the material along a single lattice plane through a distance of about a thousand atomic diameters. Moreover, there is much evidence that the steps on the surface which appear as slip bands attain their full height in a small fraction of a second, though their length may thereafter increase slowly. At higher temperatures and at slow rates of strain the slip bands appear, under the electron microscope, as clusters of lines about a hundred atomic diameters apart. The origin of slip lines, the reason for this clustering and the cause of work-hardening are discussed. The two conceptions used in the discussion are the dislocation line and the vacant lattice site. Slip lines are believed to have their origin in a certain arrangement of dislocation lines of frequent occurrence in the interior of the crystal. These are known as Frank-Read sources; their relation to recent work on the growth of crystals is shown. Where a slip line terminates dislocations must remain in the crystal; to the internal strains round these is ascribed work-hardening, much as in Taylor's theory of 1934†. It is now, however, possible to explain what it is that stabilizes the dislocations and prevents them from moving back when the stress is released. Finally, vacant lattice sites are shown to be formed in a cold-worked material. If the temperature is high enough for them to diffuse, they soften the material round the slip band and allow the observed clusters to form. They also play a part in producing the observed “fragmentation” of cold-worked material.

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