Nucleation-Mediated Structural Refinement and Aluminium Alloy Design

2006 ◽  
Vol 519-521 ◽  
pp. 191-196 ◽  
Author(s):  
Barry C. Muddle ◽  
Jian Feng Nie
Keyword(s):  
Amorphous Matrix ◽  
Thermomechanical Processing ◽  
Nanocrystalline Structure ◽  
Al Alloys ◽  
Grain Structure ◽  
Second Phase ◽  
Structural Refinement ◽  
Second Phase Particles ◽  
Solid State Phase Transformation ◽  
Structural Scale

Regardless of whether it is cast microstructure, the grain structure that is the product of thermomechanical processing or the nanoscale dispersions of strengthening second-phase particles, it is inescapable that the structural scale that controls mechanical properties in Al alloys is determined primarily by processes of nucleation during either solidification, recrystallisation or solid-state phase transformation. In those advanced alloys with bulk amorphous or nanocrystalline structure, production of an amorphous precursor is reliant on initial suppression of the nucleation of crystallisation, and subsequent controlled nucleation of dispersed nanocrystals within amorphous matrix. The processes of nucleation that control structural scale in modern Al alloys are briefly reviewed, with a focus on potential for further structural refinement and advances in properties.

Dependence of fracture toughness on multiscale second phase particles in high strength Al alloys

2003 ◽  
Vol 19 (7) ◽  
pp. 887-896 ◽  
Author(s):  
G. Liu ◽  
G.-J. Zhang ◽  
X.-D. Ding ◽  
J. Sun ◽  
K.-H. Chen
Keyword(s):  
Fracture Toughness ◽  
High Strength ◽  
Al Alloys ◽  
Second Phase ◽  
Second Phase Particles

scholarly journals Formability of Magnesium Alloys AZ80 and ZE10

2014 ◽  
Vol 622-623 ◽  
pp. 284-291 ◽  
Author(s):  
Timotius Pasang ◽  
V. Satanin ◽  
M. Ramezani ◽  
M. Waseem ◽  
Thomas Neitzert ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloys ◽  
Strain Ratio ◽  
Grain Structure ◽  
Second Phase ◽  
Plastic Strain Ratio ◽  
Heat Treated ◽  
Second Phase Particles ◽  
Az80 Alloy ◽  
Hardening Coefficient

Formability of two magnesium alloys, namely, AZ80 and ZE10, has been investigated. Both alloys were supplied with a thickness of 0.8 mm. The grain structure of the as-received AZ80 alloy showed dislocations, twins and second-phase particles and-/or precipitates distributed uniformly within grains. These were not obvious on the ZE10 alloy. The investigations were carried out at room temperature for both alloys in the as-received and heat treated conditions (410oC for 1 hour followed by water quench). The heat treatment significantly changed the grain structure of the AZ80 alloy, but did not affect the ZE10 alloy apart from grain enlargement. The formability was studied on the basis of plastic strain ratio (r) and strain hardening coefficient (n) by means of tensile testing. In the as-received condition, the ZE10 alloy had a slightly better formability () than AZ80 alloy. Following heat treatment, however, the formability of the AZ80 alloy was improved significantly (by about 26%), while the ZE10 alloy did not show any significant change.

Non-Heat Treatable Al-Alloys: Development of Intermetallic Particles during Solidification and Homogenization

2019 ◽  
Author(s):  
Olaf Engler ◽  
Katrin Kuhnke ◽  
Jochen Hasenclever
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Al Alloys ◽  
Alloying Elements ◽  
Second Phase ◽  
Phase Selection ◽  
Industrial Processing ◽  
Intermetallic Particles ◽  
Second Phase Particles

The materials properties of Al-alloys are controlled by the added alloying elements and by the processing conditions through the resulting materials microstructure. An important aspect in the description of the microstructure is the constitution of the material in terms of alloying elements in solid solution and, in turn, volume, size, morphology, and species of second-phase particles. These constitutional characteristics, conveniently summarized as microchemistry, have an impact on physical properties like thermal or electrical conductivity and on mechanical properties including strength and formability of Al-alloys. In the present article, we summarize the phase selection upon solidification and the changes in microchemistry during subsequent homogenization annealing during conventional industrial processing of non-heat-treatable Al wrought alloys.

Influence of Second-Phase Particles on Microstructure Evolution and Mechanical Behavior of Ultrafine Grained Al-Alloys Produced by Severe Plastic Deformation

2010 ◽  
Vol 89-91 ◽  
pp. 521-526
Author(s):  
Wei Ping Hu ◽  
Rolf Berghammer ◽  
Zhen Shan Liu ◽  
Si Jia Mu ◽  
Günter Gottstein
Keyword(s):  
Plastic Deformation ◽  
Microstructure Evolution ◽  
Al Alloys ◽  
Second Phase ◽  
Two Phase ◽  
Ultrafine Grained ◽  
Second Phase Particles ◽  
Die Pressing ◽  
Mechanical Behaviours ◽  
Confined Channel

In present investigation the influence of second phase particles on microstructure evolution during confined channel-die pressing (CCDP) and mechanical behaviour after CCDP were studied using two-phase Al alloys of Al-1.5Mn and Al-5Zn-1.6Mg. The investigation results revealed different grain refinement kinetics during CCDP and distinct mechanical behaviours after CCDP for both alloys. The results are discussed based on the influence of the second phase particles on dynamic recovery and the interaction with mobile dislocations during plastic deformation.

scholarly journals Simulation of the Recrystallization Textures of Al-Alloys on the Basis of Nucleation and Growth Probability of the Various Textures Components

1997 ◽  
Vol 28 (3-4) ◽  
pp. 197-209 ◽  
Author(s):  
O. Engler
Keyword(s):  
Rolling Texture ◽  
Nucleation Site ◽  
Al Alloys ◽  
Second Phase ◽  
Nucleation Sites ◽  
Second Phase Particles ◽  
Growth Selection ◽  
Cold Rolled ◽  
Limited Spectrum ◽  
Growth Probability

The recrystallization textures of cold rolled Al-alloys are simulated under the assumption of a growth selection of the typical recrystallization texture components out of a limited spectrum of preferentially formed nucleus orientations. The probability of nucleation is derived from the distribution of the potential nucleus orientations which was determined by EBSD local texture analysis for the most important nucleation sites in cold rolled commercial Al-alloys, i.e. Cube-bands, grain boundaries and second phase particles. If several nucleation sites are active simultaneously, the total nucleation probability is composed of the respective contributions of each nucleation site. The growth probability is derived from a 40°<111> transformation of the rolling texture. The resulting recrystallization textures are simulated by multiplying these two probability functions, i.e. the ODF of the nucleus orientations with the ODF of the 40°<111>-transformed rolling texture.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

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