Effects of Sn Addition on Clustering and Age-Hardening Behavior in a Pre-Aged Al-Mg-Si Alloy

2016 ◽  
Vol 877 ◽  
pp. 455-460 ◽  
Author(s):  
Hisao Shishido ◽  
Yasuo Takaki ◽  
Masaya Kozuka ◽  
Katsushi Matsumoto ◽  
Yasuhiro Aruga
Keyword(s):  
Cluster Formation ◽  
Natural Aging ◽  
Atom Probe ◽  
The Other ◽  
Endothermic Peak ◽  
Age Hardening ◽  
Number Density ◽  
Scanning Calorimetry ◽  
Hardening Behavior ◽  
Other Hand

The effects of Sn addition on clustering and age-hardening behavior in an Al-0.6Mg-1.0Si (mass %) alloy were investigated. Addition of Sn delayed the age-hardening in single aging at 170 ̊C. On the other hand, Sn promoted the age-hardening response in 3-step aging process which comprises a pre-aging (PA) at 90 ̊C for 18ks followed by natural aging (NA) for 604.8ks and artificial aging (AA) at 170 ̊C. The characteristics of clusters formed during PA and NA were evaluated by differential scanning calorimetry (DSC) analysis and atom probe tomography (APT). The DSC results show that the endothermic peak at around 160 ̊C to 200 ̊C was observed in the Sn-free alloy. On the other hand, in the Sn-added alloy, endothermic peak was not observed. It is suggested that Sn addition suppresses the formation of the clusters formed during NA. The APT results show that the Sn addition decreases the number density of clusters, especially smaller clusters. No Sn precipitates were found in Mg-Si precipitates formed during AA at 170 ̊C for 3.6ks. It is speculated that suppression of smaller cluster formation by addition of Sn promotes the age-hardening response

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.

Effects of Pre-Aging and Natural Aging on Bake Hardening Behavior in Al-Mg-Si Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 1026-1031 ◽  
Author(s):  
Yasuo Takaki ◽  
Yasuhiro Aruga ◽  
Masaya Kozuka ◽  
Tatsuo Sato
Keyword(s):  
Aging Time ◽  
Early Stage ◽  
Natural Aging ◽  
Hardness Test ◽  
Age Hardening ◽  
Bake Hardening ◽  
Scanning Calorimetry ◽  
Hardening Behavior ◽  
Β Phase ◽  
Cluster 2

The effects of pre-aging and natural aging on the bake hardening behavior of Al-0.62Mg-0.93Si (mass%) alloy with multi-step aging process were investigated by means of Vickers hardness test, tensile test, differential scanning calorimetry analysis (DSC) and transmission electron microscopy (TEM). The characteristics of nanoclusters (nano scale solute atom clusters) formed during pre-aging and natural aging were also investigated using the three dimensional atom probe (3DAP) analysis. The results revealed the occurrence of natural age hardening and that the bake hardening response was decreased after the extended natural aging even though the pre-aging was conducted before natural aging. Since the 3DAP results exhibited the Si-rich clusters were newly formed during extended natural aging, it was assumed that the Si-rich clusters caused the natural age hardening and the reduced bake hardening response corresponding to Cluster(1). The decrease of the bake hardening response was markedly higher in the later stage of bake hardening than in the early stage. The size of the β’’ precipitates were reduced with increasing the natural aging time. Exothermic peaks of Peak 2 and Peak 2’ were observed in the DSC curves for the alloys pre-aged at 363K. Peak 2’ became larger with the natural aging time. This is well understood by the following model. The transition from Cluster(2) to the β’’ phase occurs preferentially at the early stage of the bake hardening. Then the growth of the β’’ phase is inhibited by the presence of Cluster(1) at the later stage of bake hardening. The combined formation of Cluster(1) and Cluster(2) by the multi-step aging essentially affects the bake hardening response and the β’’ precipitates in the Al-Mg-Si alloys.

Nano-Scale Clusters Formed in the Early Stage of Phase Decomposition of Al-Mg-Si Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 357-360 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Tatsuo Sato
Keyword(s):  
Early Stage ◽  
Sheet Material ◽  
Three Dimensional ◽  
Natural Aging ◽  
Aging Treatment ◽  
Atom Probe ◽  
Phase Decomposition ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Nano Scale

The formation of nano-scale clusters (nanoclusters) prior to the precipitation of the strengthening b” phase significantly influences two-step aging behavior of Al-Mg-Si alloys. In this work, the existence of two kinds of nanoclusters has been verified in the early stage of phase decomposition by differential scanning calorimetry (DSC) and three-dimensional atom probe (3DAP). Pre-aging treatment at 373K before natural aging was also found to form preferentially one of the two nanoclusters, resulting in the remarkable restoration of age-hardenability at paint-bake temperatures. Such microstructural control by means of optimized heat-treatments; i.e. nanocluster assist processing (NCAP), possesses great potential for enabling Al-Mg-Si alloys to be used more widely as a body-sheet material of automobiles.

scholarly journals Effects of Natural Aging on Age-Hardening Behavior of Cu-Be-Co and Cu-Ti Alloys Processed by High-Pressure Torsion

2016 ◽  
Vol 57 (9) ◽  
pp. 1471-1475 ◽  
Author(s):  
Chihiro Watanabe ◽  
Masakazu Hibino ◽  
Ryoichi Monzen ◽  
Seiichiro Ii ◽  
Koichi Tsuchiya
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Natural Aging ◽  
Age Hardening ◽  
Hardening Behavior ◽  
Ti Alloys

scholarly journals Ferritin and Ferruginous Micelles in Normal Erythroblasts and Hypochromic Hypersideremic Anemias

Blood ◽  
1959 ◽  
Vol 14 (4) ◽  
pp. 423-432 ◽  
Author(s):  
MARCEL C. BESSIS ◽  
JANINE BRETON-GORIUS
Keyword(s):  
Lead Poisoning ◽  
Iron Metabolism ◽  
Cluster Formation ◽  
Fetal Hemoglobin ◽  
Optical Microscope ◽  
The Other ◽  
Hemoglobin Synthesis ◽  
Other Hand ◽  
Granular Particles

Abstract 1. All normal erythroblasts contain some iron in the ferritin form. It may be present in either a dispersed state or in compact clusters. When large enough, these clusters may be observed in the optical microscope: they are the granular particles of the siderocytes. 2. Iron can be found in the mitochondria. It may exist either in the form of ferritin granules or as ferruginous micelles. 3. In thalassemia, large quantities of iron accumulate in the erythroblasts and are even found in the erythrocytes as ferritin, in cluster formation or dispersed. Occasionally, iron is present in great quantities in the mitochondria as ferritin or micelles. It seems that the various disorders encountered in thalassemia may thus be ascertained; the disturbance in hemoglobin synthesis results in the accumulation of the unused iron in the hypochromic erythrocytes. 4. In diseases very similar to thalassemia and in which no fetal hemoglobin is found, i.e., the hypochromic-hypersideremic anemias (sidero-achestic anemia, hypochromic hypersideremic anemia, lead-poisoning ), similar findings are observed. 5. Normally, it is probable that iron metabolism occurs in the mitochondria. In thalassemia and hypochromic hypersideremic anemias, on the other hand, iron metabolism often appears to be "blocked" in the same areas.

scholarly journals Effects of Natural Aging on Age-Hardening Behavior of Cu-Be-Co and Cu-Ti Alloys Severely Deformed by High-Pressure Torsion

2017 ◽  
Vol 58 (10) ◽  
pp. 1346-1350 ◽  
Author(s):  
M. Hibino ◽  
C. Watanabe ◽  
Y. Tsuji ◽  
R. Monzen ◽  
Y. Todaka ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Natural Aging ◽  
Age Hardening ◽  
Hardening Behavior ◽  
Ti Alloys

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.

Effects of Zn Addition and Aging Condition on Serrated Flow in Al-Mg Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 483-488 ◽  
Author(s):  
Katsushi Matsumoto ◽  
Yasuhiro Aruga ◽  
Hidemasa Tsuneishi ◽  
Hikaru Iwai ◽  
Masataka Mizuno ◽  
...  
Keyword(s):  
Artificial Aging ◽  
Flow Behavior ◽  
Natural Aging ◽  
Atom Probe ◽  
Mg Alloys ◽  
Scanning Calorimetry ◽  
Serrated Flow ◽  
Zn Addition ◽  
Al Mg Alloys ◽  
Zn Alloys

The serrated flow phenomena in Al-Mg alloys with and without Zn were investigated after aging on several conditions, focusing on the role of precipitates. Al-6mass%Mg-0~3mass%Zn alloys were solution treated at 753~803K, quenched, and then aged at room temperature. Further artificial aging at 323~573K for 86.4ks was performed for some of them after natural aging for 2.6Ms. The serrated flow behavior was evaluated by tensile test. Microstructure was characterized by differential scanning calorimetry, transmission electron microscopy, atom probe tomography, and positron annihilation lifetime spectroscopy. The increase in the amount of Zn addition and the natural aging time lead to a delayed onset of serrated flow. The artificial aging at higher temperatures after natural aging, on the other hand, decreases the onset strain. A large number of small coherent Zn-Mg clusters are formed during natural aging in the Al-Mg-Zn alloys, which are transformed to the larger incoherent meta-stable precipitates during subsequent artificial aging. These results suggest that the mechanism of interfering with serrated flow is related to the vacancy trapping effect, which is enhanced by the coherent clusters.

scholarly journals Influence of Zn and Sn on the Precipitation Behavior of New Al–Mg–Si Alloys

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2547
Author(s):  
Felix Glöckel ◽  
Peter J. Uggowitzer ◽  
Peter Felfer ◽  
Stefan Pogatscher ◽  
Heinz Werner Höppel
Keyword(s):  
Yield Strength ◽  
Cluster Formation ◽  
Tensile Tests ◽  
Atom Probe ◽  
Aged Condition ◽  
Hardening Behavior ◽  
Formation Kinetics ◽  
Hardness Tests ◽  
Standard Alloy ◽  
Strength Increment

In this study, we demonstrate how Zn and Sn influence hardening behavior and cluster formation during pre-aging and paint bake treatment in Al–Mg–Si alloys via hardness tests, tensile tests, and atom probe tomography. Compared to the standard alloy, the Sn-modified variant shows reduced cluster size and yield strength in the pre-aged condition. During the paint bake cycle, the clusters start to grow very fast and the alloy exhibits the highest strength increment. This behavior is attributed to the high vacancy binding energy of Sn. Adding Zn increases the formation kinetics and the size of Mg–Si co-clusters, generating higher yield strength values for both the pre-aged and paint baked conditions. Simultaneous addition of Zn and Sn creates a synergistic effect and produces an alloy that exhibits moderate strength (and good formability) in the pre-aged condition and accelerated hardening behavior during the paint bake cycle.

scholarly journals Study on the Method of Identifying Ultrafine Bubbles Using Ultrasound under the Presence of Solid Nanoparticles

2021 ◽  
Vol 333 ◽  
pp. 01001
Author(s):  
Naoya Yamawaki ◽  
Hayato Okumura ◽  
Shigenori Akamatsu ◽  
Yusuke Nishiuchi ◽  
Takashi Hata
Keyword(s):  
Potassium Iodide ◽  
Luminescence Intensity ◽  
Solid Particles ◽  
The Other ◽  
Distinct Difference ◽  
Oh Radicals ◽  
Number Density ◽  
Ultrasound Frequency ◽  
Other Hand ◽  
The Difference

The method of making OH radicals generated by the collapse of ultrafine bubbles as an indicator when applying ultrasound was examined as the method of identifying ultrafine bubbles less than 1 μm in diameter under the presence of mixed solid nanoparticles. First, potassium iodide (KI) method was used to evaluate OH radicals. Since difference in absorbance due to OH radicals generated by the collapse of ultrafine bubbles is very small when using air as contained gas, evaluation using the KI method was difficult; however, a distinct difference in absorbance was confirmed by increasing the amount of OH radicals generated by using ozone as contained gas. Moreover, the higher the ultrasound frequency, the greater the difference in absorbance. On the other hand, a luminescence phenomenon related to the collapse of ultrafine bubbles by ultrasound was confirmed with sonoluminescence observation, confirming further that the luminescence intensity of water added with solid particles of the same diameter and number density as those of ultrafine bubbles is smaller than that of ultrafine bubble water.

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