TEM investigations of the structural evolution in a pearlitic steel deformed by high-pressure torsion

Wetscher, Florian; Pippan, Reinhard; Šturm, Sašo; Kauffmann, Florian; Scheu, Christina; Dehm, Gerhard

doi:10.1007/s11661-006-0138-3

Cited by 104 publications

(42 citation statements)

References 28 publications

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“…The disk after 20 turns by HPT gives a gradient-type microstructure where the central region towards a radius of r ≈ 2.5 mm shows a multi-layered formation of Al-rich and Mgrich phases while the outer region at r > 2.5 mm reveals a complete mixing of these two phases. Using conventional analysis [20][21][22], the outer region showing a mixture of Al and Mg phases has an estimated equivalent von Mises strain of ~230-460 due to torsional straining and the consequent gradient structure is consistent with results reported earlier for disks processed up to 10 HPT turns [14][15][16].…”

Section: Experimental Materials and Proceduressupporting

confidence: 86%

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

Han

Lee

Jang

et al. 2017

Materials Science and Engineering: A

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High-pressure torsion (HPT) is one of the major severe plastic deformation (SPD) procedures where bulk metals, in the shape of a disk, achieve exceptional grain refinement at ambient temperatures. HPT has been applied for the consolidation of metallic powders and the bonding of machining chips whereas there are very limited reports examining the application of HPT for the production of new metal systems and the formation of nanocomposites. Accordingly, this investigation was initiated to evaluate the potential for the formation of a metal matrix nanocomposite (MMNC) by processing two commercial metal disks of an Al-1050 alloy and a ZK60 magnesium alloy through HPT under 6.0 GPa for 20 turns at room temperature. Evolutions in microstructure, mechanical properties including hardness and plasticity and the tribological properties were examined in the MMNC region of the processed Al-Mg system. The significance of post-deformation annealing (PDA) at 573 K for 1 hour was investigated by the change in microstructure and the enhancement in mechanical properties and wear resistance of the HPT-processed MMNC. This study demonstrates the promising feasibility of using HPT to fabricate a wide range of hybrid MMNCs from simple metals and for applying PDA for further improvement of the essential mechanical and tribological properties in the synthesized alloy systems.

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Section: Experimental Materials and Proceduressupporting

confidence: 86%

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

Han

Lee

Jang

et al. 2017

Materials Science and Engineering: A

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“…In this case this process can be related to a softening of the material. [53] Recently it has been shown that severe plastic deformation can dissolve very stable phases [54][55][56][57][58][59][60][61][62] similar to the phenomena reported from ball milling. [63][64][65][66][67] A CuFe filamentary composite has been deformed by HPT.…”

Section: Mechanical Alloying By Spdmentioning

confidence: 79%

“…The most apparent feature of the deformed pearlitic steel is the alignment of the cementite lamellae to the shear direction. [50,60,61] The lamellae spacing decreases and the size of the fragmented ferrite is limited by the lamellae spacing. [50] This decreasing of the lamellae spacing and partly fracturing of the "cementite" lamellae is clearly seen in Figure 17.…”

Section: Mechanical Alloying By Spdmentioning

confidence: 99%

The Limits of Refinement by Severe Plastic Deformation

et al. 2006

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The effect of the different processing parameters on the refinement during severe plastic deformation is evaluated. The attention is focused to very high strains, where saturation in the structural refinement is observed. The single phase metals and alloys show a relatively uniform behaviour, with increasing strain the size of structural elements decreases and reaches saturation between equivalent strains of 5 to 50. The resulting ultra fine or nanostructured granular microstructure contains mainly high angle grain boundaries. Alloying, the temperature, and the strain path are the most important parameters controlling the saturation in the structural refinement. The behavior of the dual and multiphase materials during SPD is more complex, it varies from simple homogenisation of the phase distribution, fragmentation of one phase to disintegration and supersaturation of the phases. Severe plastic deformation of these types of materials offers the potential for the production of new types of materials with a nanocrystalline or a nanocomposite structure for a broad range of industrial applications.

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“…It is well established that the equivalent von Mises strain, ε, may be estimated in HPT using the relationship [133][134][135] …”

Section: The Occurrence Of Dynamic Recovery During Hpt Processingmentioning

confidence: 99%

The significance of self-annealing at room temperature in high purity copper processed by high-pressure torsion

Huang

Sabbaghianrad

Almazrouee

et al. 2016

Materials Science and Engineering: A

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High purity copper was processed by high-pressure torsion (HPT) at room temperature and then stored at room temperature for periods of up to 6 weeks to investigate the effect of self-annealing. Hardness measurements were recorded both at 48 h after HPT processing and after various storage times. The results show the occurrence of recovery near the edges of the discs after processing through 1/2 and 1 turn and this leads to a significant drop in the measured hardness values which is accompanied by microstructural evidence for abnormal grain growth. Conversely, there was no recovery, and therefore no hardness drops, after processing through 5 and 10 turns. X-ray line profile analysis was used to determine the crystallite sizes and dislocation densities at 1 h after HPT and after storage for different times.The results show a good thermal stability in high purity Cu after processing through more than 1 turn of HPT but care must be exercised in recording hardness measurements when processing through only fractional or very small numbers of turns.

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TEM investigations of the structural evolution in a pearlitic steel deformed by high-pressure torsion

Cited by 104 publications

References 28 publications

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

The Limits of Refinement by Severe Plastic Deformation

The significance of self-annealing at room temperature in high purity copper processed by high-pressure torsion

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