Superplasticity of Aerospace 7075 (Al-Zn-Mg-Cu) Aluminium Alloy Obtained by Severe Plastic Deformation

2018 ◽  
Vol 385 ◽  
pp. 39-44 ◽  
Author(s):  
Fernando Carreño ◽  
Oscar A. Ruano
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Aluminium Alloy ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
Aerospace Applications ◽  
Boundary Sliding ◽  
Processing Stress

The 7075 (Al-Zn-Mg-Cu) aluminium alloy is the reference alloy for aerospace applications due to its specific mechanical properties at room temperature, showing excellent tensile strength and sufficient ductility. Formability at high temperature can be improved by obtaining superplasticity as a result of fine, equiaxed and highly misoriented grains prone to deform by grain boundary sliding (GBS). Different severe plastic deformation (SPD) processing routes such as ECAP, ARB, HPT and FSP have been considered and their effect on mechanical properties, especially at intermediate to high temperatures, are studied. Refined grains as fine as 100 nm and average misorientations as high as 39o allow attainment of high strain rate superplasticity (HSRSP) at lower than usual temperatures (250-300oC). It is shown that increasing misorientations are obtained with increasing applied strain, and increasing grain refinement is obtained with increasing processing stress. Thus, increasing superplastic strains at higher strain rates, lower stresses and lower temperatures are obtained with increasing processing strain and, specially, processing stress.

The Effect of Grain Boundary State on Deformation Process Development in Nanostructured Metals Produced by the Methods of Severe Plastic Deformation

2011 ◽  
Vol 683 ◽  
pp. 69-79 ◽  
Author(s):  
Evgeny V. Naydenkin ◽  
Galina P. Grabovetskaya ◽  
Konstantin Ivanov
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Severe Plastic Deformation ◽  
Deformation Process ◽  
Process Development ◽  
Grain Boundary Sliding ◽  
Total Deformation ◽  
Nanostructured Metals ◽  
Boundary State ◽  
Boundary Sliding

In this review the investigations of deformation process development are discussed which were carried out by tension and creep in the temperature range Т<0.4Tm (here Тm is the absolute melting point of material) for nanostructured metals produced by the methods of severe plastic deformation. The contribution of grain boundary sliding to the total deformation in the above temperature interval is also considered. An analysis is made of the effect of grain size and grain boundary state on the evolution of grain boundary sliding and cooperative grain boundary sliding in nanostructured metals.

scholarly journals Is Superplasticity in the Future of Nanophase Materials?

1990 ◽  
Vol 196 ◽  
Author(s):  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Atomic Clusters ◽  
Diffusional Creep ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Nanophase Materials ◽  
Boundary Sliding

ABSTRACTThe ultrafine grain sizes and high diffusivities in nanophase materials assembled from atomic clusters suggest that these materials may have a strong tendency toward superplastic mechanical behavior. Both small grain size and enhanced diffusivity can be expected to lead to increased diffusional creep rates as well as to a significantly greater propensity for grain boundary sliding. Recent mechanical properties measurements at room temperature on nanophase Cu, Pd, and TiO2, however, give no indications of superplasticity. Nonetheless, significant ductility has been clearly demonstrated in these studies of both nanophase ceramics and metals. The synthesis of cluster-assembled nanophase materials is described and the salient features of what is known of their structure and mechanical properties is reviewed. Finally, the answer to the question posed in the title is addressed.

Superplasticity in a 5024 Aluminium Alloy Processed by Severe Plastic Deformation

2012 ◽  
Vol 735 ◽  
pp. 353-358 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Tagirova ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Initial Strain Rate ◽  
Strain Rates ◽  
Superplastic Behaviour ◽  
Angular Pressing ◽  
Elongation To Failure ◽  
Zr Alloy

The superplastic behaviour of an Al-4.6%Mg-0.35%Mn-0.2%Sc-0.09%Zr alloy was studied in the temperature range 250-500°C at strain rates ranging from 10-4 to 10-1 s-1. The AA5024 was subjected to equal channel angular pressing (ECAP) at 300°C up to ~12. The highest elongation-to-failure of ∼3300% was attained at a temperature of 450°C and an initial strain rate of 5.6×10-1 s-1. Regularities of superplastic behaviour of the 5024 aluminium alloy are discussed.

Current States and Development of Research on Redissolution and Reprecipitation of Nanoprecipitated Phases in Al–Cu Alloys

2019 ◽  
Vol 11 (11) ◽  
pp. 1489-1501
Author(s):  
Wenjing He ◽  
Caihe Fan ◽  
Shu Wang ◽  
Junhong Wang ◽  
Su Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
Supersaturated Solid Solution ◽  
Aluminum Matrix ◽  
Aging Treatment ◽  
Cu Alloys ◽  
The Reformation

The evolution of nanoprecipitated phases in Al–Cu alloys under severe plastic deformation (SPD) is summarized in this study. SPD at room temperature induces the precipitation of Al–Cu alloys to dissolve, leading to the reformation of supersaturated solid solution in the aluminum matrix. In the process of SPD or aging treatment after the SPD, the reprecipitated phases are precipitated from the aluminum matrix and the mechanical properties of the alloys are remarkably improved. The mechanism and system of the redissolution of the precipitation phases and the effects of redissolution and reprecipitation on the microstructure and properties of Al–Cu alloys are comprehensively analyzed. The development and future of redissolution and reprecipitation of nanoprecipitated phases in Al–Cu alloys are also described.

Strain-Rate Sensitivity Enhanced by Grain-Boundary Sliding in Creep Condition for AZ31 Magnesium Alloy at Room Temperature

2016 ◽  
Vol 838-839 ◽  
pp. 106-109 ◽  
Author(s):  
Tetsuya Matsunaga ◽  
Hidetoshi Somekawa ◽  
Hiromichi Hongo ◽  
Masaaki Tabuchi
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
High Strain ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
High Strain Rates ◽  
Boundary Sliding

This study investigated strain-rate sensitivity (SRS) in an as-extruded AZ31 magnesium (Mg) alloy with grain size of about 10 mm. Although the alloy shows negligible SRS at strain rates of >10-5 s-1 at room temperature, the exponent increased by one order from 0.008 to 0.06 with decrease of the strain rate down to 10-8 s-1. The activation volume (V) was evaluated as approximately 100b3 at high strain rates and as about 15b3 at low strain rates (where b is the Burgers vector). In addition, deformation twin was observed only at high strain rates. Because the twin nucleates at the grain boundary, stress concentration is necessary to be accommodated by dislocation absorption into the grain boundary at low strain rates. Extrinsic grain boundary dislocations move and engender grain boundary sliding (GBS) with low thermal assistance. Therefore, GBS enhances and engenders SRS in AZ31 Mg alloy at room temperature.

Influence of Temperature of Severe Plastic Deformation and Aging on Microstructure, Mechanical Properties and Electrical Conductivitiy of the Cu-Cr-Zr Alloy

2018 ◽  
Vol 385 ◽  
pp. 273-277
Author(s):  
Elena Sarkeeva ◽  
Marina M. Abramova ◽  
Igor V. Alexandrov
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Influence Of Temperature ◽  
Annealed Copper ◽  
Thermal Stability Of ◽  
Zr Alloy

The article studies an influence of temperature of severe plastic deformation (SPD) and post-deformation heat treatment on microstructure, mechanical properties and thermal stability of the Cu-0.5Cr-0.2Zr alloy. The results demonstrate that strength is considerably increased to 900 MPa by high pressure torsion (HPT) at room temperature. Subsequent ageing at 450 °С during 1 hour leads to a decay of solid solution and an allocation of dispersion particles that further incrises strength to 900 MPa, restores electrical conductivity to 70% IACS (International annealed copper standard) and enhances thermal stability of the alloy. When deformation temperature is increased to 300°С, strength is 690 MPa that is lower than in the case of deformation at room temperature that is related to reversion process at deformation. Additional a aging does not lead to an increase of strength characteristics.

Transient Negative Strain Hardening during Severe Plastic Deformation of Al-30wt%Zn Alloys

2013 ◽  
Vol 554-557 ◽  
pp. 3-11 ◽  
Author(s):  
Marina Borodachenkova ◽  
José Grácio ◽  
Frédéric Barlat ◽  
Catalin R. Picu
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Mean Free Path ◽  
Grain Boundary Sliding ◽  
Evolution Law ◽  
Boundary Sliding ◽  
The Mean ◽  
Softening Process ◽  
The Relationship ◽  
Zn Alloys

In this work we propose a new model (SOFTMAR) to describe the transient softening observed during severe plastic deformation of Al-30wt%Zn alloys. The model is divided in two main parts. The first one describes the softening process based on the evolution law of the mean free path of dislocations (L) with plastic strain . In the second part of the model emphazis is given to the relationship between the grain size and strain rate that in turn depends on diffusion-driven grain-boundary sliding.

The Influence of Hydrostatic Extrusion on the Microstructure of 6082 Aluminium Alloy

2006 ◽  
Vol 114 ◽  
pp. 145-150 ◽  
Author(s):  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Małgorzata Lewandowska ◽  
Wacław Pachla ◽  
Mariusz Kulczyk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Severe Plastic Deformation ◽  
Light Microscopy ◽  
Aluminium Alloy ◽  
Extrusion Process ◽  
Hydrostatic Extrusion ◽  
Fine Grained

Hydrostatic extrusion can be viewed as one of the methods of Severe Plastic Deformation, SPD, for the fabrication of ultra-fine grained alloys which causes a significant increase in the mechanical properties such as tensile strength and hardness. In the present study the microstructure of 6082 aluminium alloy after hydrostatic extrusion was investigated. Hydroextrusion was performed in three steps with accumulated true strains of 1.34, 2.73 and 3.74 respectively. Microstructural observations were carried out using SEM, TEM and light microscopy. Grain and inclusion sizes, shapes and distribution were investigated in the HE processed samples. The study has shown that the hydrostatic extrusion process results in a profound refinement of both the grain size and the inclusions in 6082 aluminium alloy.

Sign in / Sign up

Export Citation Format

Share Document