Three Strategies to Achieve Concurrent Strengthening by Ultrafine-Grained and Precipitation Hardenings for Severely Deformed Age-Hardnable Aluminum Alloys

2016 ◽  
Vol 1135 ◽  
pp. 161-166 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Yong Peng Tang ◽  
Zenji Horita ◽  
Seung Won Lee ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Age Hardening ◽  
Cu Alloy ◽  
Ultrafine Grained ◽  
Δ Phase ◽  
Microalloying Elements ◽  
Wrought Aluminum Alloys

In this paper, comprehensive studies on the age-hardening behavior and precipitate microstructures of severely deformed and then artificially aged aluminum alloys have been conducted to clarify whether or not concurrent strengthening by ultrafine-grained and precipitation hardenings can be achieved. From our graphically-illustrated equivalent strain dependence of both the attained hardness and increment/decrement in hardness during aging (i.e. age-hardenability), three strategies to maximize the combined processing of severe plastic deformation and age-hardening technique are proposed. (1) Lowering of aging temperature and (2) utilization of microalloying elements can improve not only the attained hardness but also the age-hardenability of high-pressure torsion (HPT) specimens of Al-Mg-Si (-Cu) alloy due to the increased volume fraction of transgranular precipitates. A further increase in hardness can be achieved by (3) taking advantage of spinodal decomposition for HPTed Al-Li-Cu alloy, in which nanoscale precipitates of δ’ phase are successfully formed within ultrafine grains, irrespective of the higher number density of grain boundaries. The attained hardness of >HV290 in the latter alloy is almost the highest among conventional wrought aluminum alloys, and therefore our proposed strategies will be useful for designing concurrently strengthened severely-deformed age-hardenable aluminum alloys.

Enhanced Thermal Stability and Mechanical Properties of Ultrafine-Grained Aluminum Alloy

2010 ◽  
Vol 667-669 ◽  
pp. 331-336 ◽  
Author(s):  
Rinat K. Islamgaliev ◽  
Marina A. Nikitina ◽  
Aidar F. Kamalov
Keyword(s):  
Thermal Stability ◽  
Aluminum Alloy ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Coarse Grained ◽  
Dynamic Precipitation ◽  
Ultrafine Grained ◽  
The Mean ◽  
Fatigue Endurance ◽  
Thermal Stability Of

The paper reports on microstructure, strength and fatigue of ultrafine-grained (UFG) samples of the Al-Cu-Mg-Si aluminum alloy processed by high pressure torsion (HPT) at various temperatures. Application of the HPT treatment led to strong grain refinement, as well as to a raise of the mean-root square strains and dynamic precipitation. In case of optimal HPT treatment the UFG samples have demonstrated the enhanced thermal stability, an increase in ultimate tensile strength in 2.5 times and enhancement in fatigue endurance limit by 20 % in comparison with coarse-grained alloy subjected to standard treatment. It is shown that the regime of the HPT treatment governs the volume fraction of precipitates and segregations, thereby affecting a grain size and thermal stability of ultrafine-grained structure.

Strength and ductility in ultrafine-grained wrought aluminum alloys

2013 ◽  
Vol 49 ◽  
pp. 520-524 ◽  
Author(s):  
Weilin Yan ◽  
Xiaohong Liu ◽  
Jinyuan Huang ◽  
Lin Chen
Keyword(s):  
Aluminum Alloys ◽  
Ultrafine Grained ◽  
Wrought Aluminum Alloys ◽  
Wrought Aluminum ◽  
Strength And Ductility

Development of Age-Hardening Technology for Ultrafine-Grained Al-Li-Cu Alloys Fabricated by High-Pressure Torsion

2012 ◽  
pp. 939-944
Author(s):  
Hiroaki Motoshima ◽  
Shoichi Hirosawa ◽  
Seungwon Lee ◽  
Zenji Horita ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Age Hardening ◽  
Cu Alloys ◽  
Ultrafine Grained

Studies of precipitate rich-zones on grain boundaries of Al-Mg-Si alloys after aging

1978 ◽  
Vol 36 (1) ◽  
pp. 642-643
Author(s):  
Jože Pirš ◽  
Marija Pavlin
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloys ◽  
Grain Boundaries ◽  
Aging Treatment ◽  
Mg Alloy ◽  
Age Hardening ◽  
Cu Alloy ◽  
Solute Depletion ◽  
Type Of Failure

In most age-hardening aluminum alloys, metallographic studies have shown that the extent of precipitation adjacent to grain boundaries is much less than that which occurs in the interior of the grains. The width of these almost precipitate-free regions, which are sometimes called denuded zones, and the extent of solute depletion with them are dependent upon the particular alloy and its aging treatment. It has been observed that these zones are relatively soft with the result that plastic deformation takes place preferentially within them. It has been shown 2-4 that there exists a tendency for intercrystalline cracking in fatigue when such zones are present. It is of interest to note that Broom et al. were able to reduce the incidence of this type of failure in an Al- 4 wt pct Cu alloy by stretching the material 10 pct prior to aging. This was later confirmed also on Al - 10 wt pct Mg alloy.

Development of Age-Hardening Technology for Ultrafine-Grained Al-Li-Cu Alloys Fabricated by High-Pressure Torsion

2012 ◽  
pp. 939-944 ◽  
Author(s):  
Hiroaki Motoshima ◽  
Shoichi Hirosawa ◽  
Seungwon Lee ◽  
Zenji Horita ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Age Hardening ◽  
Cu Alloys ◽  
Ultrafine Grained

Strengthening mechanisms in an ultrafine-grained Al Zn Mg Cu alloy processed by high pressure torsion at different temperatures

2019 ◽  
Vol 752 ◽  
pp. 223-232 ◽  
Author(s):  
Yidong Zhang ◽  
Shenbao Jin ◽  
Patrick Trimby ◽  
Xiaozhou Liao ◽  
Maxim Y. Murashkin ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Strengthening Mechanisms ◽  
Cu Alloy ◽  
Ultrafine Grained ◽  
Different Temperatures

scholarly journals A Mathematical Model of Deformation under High Pressure Torsion Extrusion

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 306 ◽  
Author(s):  
Roman Kulagin ◽  
Yan Beygelzimer ◽  
Yuri Estrin ◽  
Yulia Ivanisenko ◽  
Brigitte Baretzky ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Die Design ◽  
Sample Length ◽  
Negative Effects ◽  
Friction Forces ◽  
Finite Element Software ◽  
Ultrafine Grained ◽  
Macro Scale

High pressure torsion extrusion (HPTE) is a promising new mechanism for severe plastic deformation of metals and alloys. It enables the manufacture of long products with a radial gradient ultrafine-grained structure and of composite materials with a helical inner architecture at the meso and the macro scale. HPTE is very promising as a technique enabling light weighting, especially with magnesium, aluminium and titanium alloys. For the first time, this article presents an analytical model of the HPTE process that makes it possible to investigate the role of the various process parameters and calculate the distribution of the equivalent strain over the entire sample length. To verify the model, its predictions were compared with the numerical simulations by employing the finite element software QForm. It was shown that potential negative effects associated with the slippage of a sample relative to the container walls can be suppressed through appropriate die design and an efficient use of the friction forces.

scholarly journals Age hardening and thermal stability of Al–Cu alloy processed by high-pressure torsion

2015 ◽  
Vol 627 ◽  
pp. 111-118 ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Yosuke Yonenaga ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Age Hardening ◽  
Cu Alloy ◽  
Thermal Stability Of

Moire Fringes on Precipitates in Quenched and Aged Beryllium

1968 ◽  
Vol 26 ◽  
pp. 426-427
Author(s):  
F. J. Fraikor ◽  
A. W. Brewer
Keyword(s):  
Ternary Phase ◽  
Volume Fraction ◽  
Age Hardening ◽  
Orientation Relationships ◽  
Solute Content ◽  
Moiré Fringes ◽  
Moire Patterns ◽  
Total Volume Fraction ◽  
Diffraction Patterns ◽  
Moiré Patterns

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.

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