A Combined TEM and Atom Probe Approach to Analyse the Early Stages of Age Hardening in AA 6016

2016 ◽  
Vol 877 ◽  
pp. 231-236 ◽  
Author(s):  
Olaf Engler ◽  
C. Schäfer ◽  
Henk Jan Brinkman ◽  
Calin D. Marioara ◽  
Masaya Kozuka ◽  
...  
Keyword(s):  
Atom Probe ◽  
Age Hardening ◽  
Artificial Ageing ◽  
Phase Decomposition ◽  
Number Density ◽  
Early Stages ◽  
Transmission Electron ◽  
Different Types ◽  
6Xxx Series ◽  
Insight Into

In this study we aim at combining the results from transmission electron microscopy (TEM) and atom probe tomography (APT) to study the early stages of phase decomposition in the age hardening alloy AA 6016. Samples are subjected to different periods of natural ageing or artificial pre-ageing at elevated temperature in order to produce different types of clusters and early stages of precipitation before age hardening commences. APT is utilized to detect clusters and identify their compositions, whereas TEM is applied to analyse and quantify number density and sizes of the particles during artificial ageing at 185°C. It is shown that the two techniques, TEM and APT, are complementary and a combined approach yields more detailed insight into the early stages of phase decomposition in age hardening 6xxx series alloys than possible by the sole use of either technique individually.

Interaction between Cu and Sn in the Early Stages of Ageing of Al-1.7at.%Cu-0.01at.%Sn

2006 ◽  
Vol 519-521 ◽  
pp. 495-500 ◽  
Author(s):  
Laure Bourgeois ◽  
Timothy Wong ◽  
X.Y. Xiong ◽  
Jian Feng Nie ◽  
Barry C. Muddle
Keyword(s):  
Three Dimensional ◽  
Atom Probe ◽  
Age Hardening ◽  
Peak Hardness ◽  
Artificial Ageing ◽  
Natural Ageing ◽  
Number Density ◽  
Transmission Electron ◽  
Hardening Treatment ◽  
Significant Acceleration

The interaction between vacancies and Sn and Cu solute atoms in an Al-1.7at.%Cu- 0.01at.%Sn alloy was investigated by exploring the effect of incorporating natural ageing into conventional age hardening treatment. It was found that provided the artificial ageing temperature does not exceed a critical value between 160°C and 200°C, a narrow window of natural ageing (3-100 h) will result in a significant acceleration of the age hardening response and no decrease in peak hardness. Transmission electron microscopy showed that this effect reflects a large and rapid increase in number density of Cu GP(I) zones, and, to a lesser extent, of θ". The distribution and number density of θ' are essentially unaffected. Three-dimensional atom probe provided strong evidence that refinement of GP(I) zone distribution is not due to clustering of Cu atoms onto pre-existing Sn clusters. Instead it appears to be caused by a subtle interaction between vacancies, Sn and Cu atoms.

Evolution of Nanostructure during the Early Stages of Ageing in Al-Zn-Mg-Cu Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 555-560 ◽  
Author(s):  
Peter V. Liddicoat ◽  
Tomoyuki Honma ◽  
L.T. Stephenson ◽  
Simon P. Ringer
Keyword(s):  
Atom Probe Tomography ◽  
Atom Probe ◽  
Age Hardening ◽  
Peak Hardness ◽  
Cu Alloys ◽  
Transmission Electron ◽  
Element Species ◽  
Hardness Increase ◽  
Solute Interactions ◽  
Effect Of Copper

During age-hardening of certain Al-Zn-Mg-Cu alloys, a 90% hardness increase can occur with 75 seconds. The clustering and precipitation of solute element species during this early rapid hardening (RH) period has been investigated through atom probe tomography, transmission electron microscopy, and Vickers hardness measurements. This study has focussed on the effect of copper by analysing three alloys; Al-2.0Zn-1.8Mg-0.7Cu, Al-2.0Zn-1.7Mg-0.2Cu and Al-1.9Zn-1.7Mg (at.%). The early RH reaction in these alloys accounts for up to 70% of the total hardening (peak hardness minus as-quenched hardness) and takes place during the first 60 seconds of ageing. We report preferred solute-solute interactions in the as-quenched materials. This quenched-in nanostructure acts as a template for subsequent solute clustering, the nature of which we have correlated with ageing.

The Effect of Pre-Ageing and Addition of Copper on the Precipitation Behaviour in Al-Mg-Si Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 543-548 ◽  
Author(s):  
A.I. Morley ◽  
M.W. Zandbergen ◽  
Alfred Cerezo ◽  
George D.W. Smith
Keyword(s):  
Aluminium Alloys ◽  
Deleterious Effect ◽  
Atom Probe ◽  
Artificial Ageing ◽  
Strengthening Effect ◽  
Natural Ageing ◽  
Aged Material ◽  
3 Dimensional ◽  
Precipitation Behaviour ◽  
6Xxx Series

Hardness measurements and 3-dimensional atom probe analysis have been used to characterise the precipitation behaviour in two 6xxx series aluminium alloys, one Cu-free alloy (Al-0.78at%Mg- 0.68at%Si) and one Cu-containing alloy (Al-0.78at%Mg-0.68at%Si-0.30at%Cu). The heat treatments consisted of either natural ageing or pre-ageing at 353K followed by a paint-bake treatment at 453K. Natural ageing was seen to increase the hardness, and hence reduce formability compared to pre-ageing. In addition, the strengthening effect of artificial ageing was less after natural ageing than after pre-ageing. In the Cu-free alloy, needle-like β″ was observed to form only after a pre-ageing treatment during the first 60 minutes of a paint-bake treatment. In the Cucontaining alloy, needle-like β″ formed during paint bake in both the naturally-aged and pre-aged material, although it is formed more rapidly after pre-ageing. This was accompanied by an increase in strength over the Cu-free alloy and indicates that Cu reduces the deleterious effect of natural ageing.

Resolving the Morphology of Niobium Carbonitride Nano-Precipitates in Steel Using Atom Probe Tomography

2014 ◽  
Vol 20 (4) ◽  
pp. 1100-1110 ◽  
Author(s):  
Andrew J. Breen ◽  
Kelvin Y. Xie ◽  
Michael P. Moody ◽  
Baptiste Gault ◽  
Hung-Wei Yen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Niobium Carbonitride ◽  
Surrounding Matrix ◽  
Transmission Electron ◽  
A New Technique ◽  
Insight Into ◽  
Reconstructed Data ◽  
Magnification Effect

AbstractAtom probe is a powerful technique for studying the composition of nano-precipitates, but their morphology within the reconstructed data is distorted due to the so-called local magnification effect. A new technique has been developed to mitigate this limitation by characterizing the distribution of the surrounding matrix atoms, rather than those contained within the nano-precipitates themselves. A comprehensive chemical analysis enables further information on size and chemistry to be obtained. The method enables new insight into the morphology and chemistry of niobium carbonitride nano-precipitates within ferrite for a series of Nb-microalloyed ultra-thin cast strip steels. The results are supported by complementary high-resolution transmission electron microscopy.

The Effect of Composition and Temperature on the Ageing Response of some Dilute 6xxx Series Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 227-232 ◽  
Author(s):  
C.N. Aiza Jaafar ◽  
Gordon W. Lorimer ◽  
N.C. Parson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solution Treatment ◽  
Precipitation Process ◽  
Microstructural Development ◽  
Solution Treatment Temperature ◽  
Artificial Ageing ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
6Xxx Series

The effects of composition and temperature on the ageing response and the microstructural development during ageing treatment of a series of dilute 6xxx series alloys have been investigated. The alloys contained between 0.22 and 0.79 wt% Si and 0.20 and 0.51 wt% Mg. Some of the alloys were copper-free, 0.001-0.002 wt% Cu, while others contained additions of 0.1 wt% Cu. Some of the alloys were ‘balanced’ while others contained excess Si (ExSi). The effects of solution treatment temperature and artificial ageing (T6) on the precipitation process were investigated using various techniques, including differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and analytical transmission electron microscopy (ATEM). MT DATA has been used to predict the phase relationships as a function of temperature and the MT DATA predictions have been compared with the phases observed by DSC and ATEM. The morphology and crystal structures of the precipitates formed were monitored by TEM. The results showed a correlation between the composition and the ageing response of the alloys.

On the Role of Characterization in the Design of Interfaces in Nanoscale Materials Technology

2004 ◽  
Vol 10 (3) ◽  
pp. 324-335 ◽  
Author(s):  
S.P. Ringer ◽  
K.R. Ratinac
Keyword(s):  
Three Dimensional ◽  
Atom Probe ◽  
Turbine Rotor ◽  
Clay Nanocomposites ◽  
Multimodal Approach ◽  
Transmission Electron ◽  
Different Types ◽  
And Control

This work reviews recent research on the design and control of interfaces in engineering nanomaterials. Four case studies are presented that demonstrate the power of a multimodal approach to the characterization of different types of interfaces. We have used a combination of conventional, high resolution, and analytical transmission electron microscopy, microbeam electron diffraction, and three-dimensional atom probe to study polymer–clay nanocomposites, turbine rotor steels used for power generation, multicomponent aluminum alloys, and nanocrystalline magnetic materials.

scholarly journals Effects of Mg Addition and Pre-Aging on the Age-Hardening Behavior in Al-Mg-Si

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1046 ◽  
Author(s):  
JaeHwang Kim ◽  
Jiwoo Im ◽  
Minyoung Song ◽  
Insu Kim
Keyword(s):  
Early Stage ◽  
Natural Aging ◽  
Age Hardening ◽  
Number Density ◽  
Hardening Behavior ◽  
Transmission Electron ◽  
Alloy Hardness ◽  
Peak Aged ◽  
Mg Addition ◽  
Cluster 2

Two types of nanoclusters, Cluster (1) and Cluster (2), formed at around room temperature and 100 °C, respectively, affect the age-hardening behavior in Al-Mg-Si alloys. Formation of Cluster (1) during natural aging (NA) is more accelerated in the high-Mg (9M10S) alloy than in the low-Mg (3M10S) alloy. Hardness at the early stage of two-step aging at 170 °C is not increased for the natural aging samples. On the other hand, hardness is directly increased for the pre-aged (PA) specimens. Furthermore, the formation of Cluster (1) during natural aging is suppressed by the formation of Cluster (2) during pre-aging at 100 °C. To understand the effects of heat treatment histories and Mg contents on the microstructure, transmission electron microscopy (TEM) was utilized. All the images were obtained at (001) plane, and peak aged samples with different heat treatments were used. Lower number density of precipitates is confirmed for the natural aging samples compared with the single-aged and pre-aged specimens. A higher number density of precipitates is confirmed for 9M10S in comparison to 3M10S. Hardness results correspond well to the TEM images.

An Analysis of the Structure of Irradiation induced Cu-enriched Clusters in Low and High Nickel Welds

2000 ◽  
Vol 650 ◽  
Author(s):  
Jonathan M. Hyde ◽  
Colin A. English
Keyword(s):  
Atom Probe ◽  
Radius Of Gyration ◽  
Number Density ◽  
Transmission Electron ◽  
Fe Content ◽  
High Nickel ◽  
Scanning Transmission ◽  
The Mean ◽  
Data Representative ◽  
Very High

ABSTRACTTwo high copper irradiated welds, one containing very low Ni and the other containing very high Ni, have been examined using 3-D atom probe (3DAP) microscopy, small angle neutron scattering (SANS) and field emission gun-scanning transmission electron microscopy (FEG- STEM).Irradiation induced clusters were observed in both welds. They were found to be significantly smaller and exist at a higher number density in the high Ni weld. A new algorithm was developed to precisely identify the shape, composition and size of clusters observed in the atom probe data. Representative irradiation induced clusters from each weld were then examined in greater detail. They were shown to be ramified and have a significant Fe content (∼60at.%). Cu was found to be more strongly associated with the core of the clusters than Mn or Ni. In the low Ni weld, there was evidence for P at the interfaces between the clusters and matrix. Cluster composition estimates from FEG-STEM analyses were consistent with those observed by 3DAP microanalysis. For each weld, the mean radius of gyration of the clusters was found to be almost identical to the radius of gyration determined directly from SANS analyses of these materials. Finally, the number density of features was estimated from the SANS data by using the compositional information from the 3DAP observations. Consistency with the number density calculated directly from the 3DAP data was obtained provided that it is assumed that the clusters exhibit some magnetic properties.

In situcharacterization of β′′ precipitation in an Al–Mg–Si alloy by anisotropic small-angle neutron scattering on a single crystal

2015 ◽  
Vol 48 (2) ◽  
pp. 455-463 ◽  
Author(s):  
Cynthia Sin Ting Chang ◽  
Frédéric De Geuser ◽  
John Banhart
Keyword(s):  
Neutron Scattering ◽  
Single Crystal ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Data ◽  
Artificial Ageing ◽  
Number Density ◽  
Transmission Electron ◽  
Repetition Time ◽  
The Impact

A single crystal of an Al–Mg–Si alloy (Mg: 0.43 wt%, Si: 0.47 wt%) was aged at 453 K while small-angle neutron scattering experiments were carried outin situ. The scattering data recorded on a two-dimensional detector show the symmetry typical for needle-shaped β′′ precipitates oriented in the three [100] directions of the aluminium lattice and allow the calculation of the length, diameter and number density of the precipitates assuming cylindrical scattering objects of equal size and composition. The repetition time of the experiments was ∼12 min. The values obtained for the three quantities agree well with values measured by transmission electron microscopy (TEM) on a similar alloy. The impact of one week of natural ageing before artificial ageing on the evolution of the size and number density of precipitates is found to be pronounced, as expected from published TEM data.

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