Aging Behavior of Al-Mg-Ge Alloys with Different Mg2Ge Contents

2011 ◽  
Vol 409 ◽  
pp. 63-66
Author(s):  
Tomoatsu Murakami ◽  
Kenji Matsuda ◽  
Takeshi Nagai ◽  
Junya Nakamura ◽  
Tokimasa Kawabata ◽  
...  
Keyword(s):  
Relative Frequency ◽  
Equilibrium Phase ◽  
Hardness Test ◽  
Age Hardening ◽  
Precipitation Sequence ◽  
Aging Behavior ◽  
Hardening Behavior ◽  
Β Phase ◽  
Hrtem Observation ◽  
Peak Aged

It is known that Al-Mg-Ge alloy shows the similar precipitation sequence to Al-Mg-Si alloy, and its equilibrium phase is β-Mg2Ge according to its phase diagram. In this study, the precipitation sequence of Al-Mg-Ge alloys containing different contents of Mg2Ge has been investigated by hardness test, TEM and HRTEM observation to understand the effect of Mg2Ge contents on age-hardening behavior of the alloys. The hardness of as-quenched and peak-aged samples have been improved by increasing Mg2Ge contents. The precipitates in the peak-aged samples have been classified into some metastable phases, such as the β’-phase and parallelogram-type precipitate by HRTEM observation. The relative frequency of these precipitates in the is has been changed with Mg2Ge contents.

TEM Observation for Precipitates Structure of Al-1.0Mass%Mg2Ge Alloys Aged at 473K

2014 ◽  
Vol 794-796 ◽  
pp. 992-995
Author(s):  
Akihiro Kawai ◽  
Keisuke Matsuura ◽  
Katsumi Watanabe ◽  
Kenji Matsuda ◽  
Susumu Ikeno
Keyword(s):  
Phase Diagram ◽  
Equilibrium Phase ◽  
Hardness Test ◽  
Age Hardening ◽  
Precipitation Sequence ◽  
Hardening Behavior ◽  
Β Phase ◽  
Hrtem Observation ◽  
Peak Aged ◽  
First Time

It is known that Al-Mg-Ge alloys show a similar precipitation sequence to that of Al-Mg-Si alloys, and that ther equilibrium phase is β-Mg2Ge according to the phase diagram. In this study, the precipitation sequence and age-hardening behavior of Al-1.0mass%Mg2Ge alloys has been investigated by hardness test, write out in full first time used TEM and HRTEM observations on.The hardness curves showed no big difference between peak values hardness for samples aged at 423, 473 and 523K. The precipitates in the peak-aged samples have been classified as some metastable phases, such as the β’-phase and parallelogram-type precipitates by HRTEM observation. The large precipitates are similar to the A-type precipitate in the Al-Mg-Si alloy with excess Si.

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.

Effect of Additional Elements (Cu, Ag) on Precipitation in 6xxx (Al-Mg-Si) Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 357-360 ◽  
Author(s):  
Kenji Matsuda ◽  
Junya Nakamura ◽  
Tokimasa Kawabata ◽  
Susumu Ikeno ◽  
Tatsuo Sato ◽  
...  
Keyword(s):  
Tensile Tests ◽  
Precipitation Sequence ◽  
Ag Addition ◽  
Hrtem Observation ◽  
Peak Aged

It has been known that Cu- or Ag-addition Al-1.0mass%Mg2Si (balanced) alloys shows higher hardness and elongation than Cu-free or Ag-free balance alloy. In this study, the alloys with Cu or Ag addition and the alloys with Si / Mg in excess have been investigated by hardness and tensile tests and HRTEM observation. Cu addition is effective for higher hardness, and Ag-addition is useful for improvement of elongation for peak-aged samples. Precipitates in peak aged these alloys have been confirmed by HRTEM. Cu-addition alloy almost includes Q’-phase, and Ag-addition alloy includes b’-phase. The precipitation sequence of Ag- or Cu addition Al-Mg-Si alloy was investigated using HRTEM, SAED, and EDS. The precipitates obtained in the two alloys were classified into several kinds by HRTEM images and SAED patterns. The relative frequencies of precipitates were also investigated and compared with that in the alloy.

HRTEM Observation of the Age Hardening Precipitates in Mg-Zn Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 157-160
Author(s):  
Shogo Mori ◽  
Tokimasa Kawabata ◽  
Kenji Matsuda ◽  
Susumu Ikeno
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Early Stage ◽  
Age Hardening ◽  
Aged Specimen ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Peak Aged ◽  
Zn Alloy ◽  
Different Parts

The age hardening precipitates of Mg-4.7mass%Zn alloy aged at 423K,473K were studied by using high-resolution transmission electron microscope (HRTEM). Contrasts of mono layers were confirmed to exist on the (0001) and (1100) matrix planes. It was considered that the contrast of mono layer was plate-like shape, and identified as pre-precipitates from as-quenched stage to early stage of aging at 473K for 32h . In the peak aged specimen of aged at 473K, the β1’ phase was observed. The β1’ phase has a rod-like shape and parallel to c-axis of Mg matrix. It can be observed orientation relationship between Mg matrix and β1’phase has not only same parts to previous reports but also different parts in one β1’ phase .

Effect of HPT on Age-Hardening Behavior in Cu-Added Excess Mg-Type Al-Mg-Si Alloys

2014 ◽  
Vol 922 ◽  
pp. 487-490
Author(s):  
Shun Maruno ◽  
Seiji Saikawa ◽  
Shoichi Hirosawa ◽  
T. Hamaoka ◽  
Z. Horita ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure Torsion ◽  
Hardness Test ◽  
Age Hardening ◽  
Work Piece ◽  
Aging Behavior ◽  
Cross Sectional ◽  
Cross Sectional Dimension ◽  
The Matrix ◽  
Excess Mg

Severe plastic deformation (SPD) techniques such as high pressure torsion (HPT) have been extensively researched to achieve. SPD process makes use of the plastic deformation where no change in the cross-sectional dimension of a work piece occurs during straining.In this work, the effect of HPT on aging behavior and microstructure in excess Mg-type Al-Mg-Si alloys including Cu. These alloys were investigated by hardness test and TEM observation. The results show that processing by HPT leads to significant grain refinement with a grain size of ~250nm. Age-hardening phenomenon is observed at 343K and 373K for the Al-Mg-Si alloys with HPT. A few density of dislocation in the crystal grain was observed. The typical needle-shaped precipitates of Al-Mg-Si alloys were not observed in the matrix.

Effect of Casting Method and Al Contents on Microstructure in AM-Type Magnesium Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 663-666 ◽  
Author(s):  
Katsumi Watanabe ◽  
Kenji Matsuda ◽  
Takumi Gonoji ◽  
Tokimasa Kawabata ◽  
Katsuya Sakakibara ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Hardness Test ◽  
Al Alloys ◽  
Age Hardening ◽  
Casting Method ◽  
Absorption Properties ◽  
Al Content ◽  
Hardening Behavior ◽  
The Difference ◽  
Impact Absorption

Magnesium alloys have received considerable attention because of their lightweight and recyclability. AM-type and AZ-type Mg-Al alloys have been used for industrial products widely, particularly for AM-type alloys because of the better toughness and impact absorption properties than AZ-type alloys. However, there is little report about the effect of casting method on age-hardening behavior and microstructure of AM-type alloys. The purpose of this study is to investigate the difference of the age-hardening behavior and microstructures of three AM-type alloys cast with steel, copper and sand molds using hardness test and scanning electron microscopy (SEM) observation. Furthermore, the effect of Al content is also investigated in this study using three alloys of AM30 (3%Al), AM60 (6%Al) and AM90 (9%Al).

Effect of Grain Size on Microstructure and Aging Behavior in AM60 Magnesium Alloy

2011 ◽  
Vol 409 ◽  
pp. 373-378
Author(s):  
H. Takano ◽  
Mitsuaki Furui ◽  
Susumu Ikeno ◽  
Tomoyasu Yamaguchi ◽  
Seiji Saikawa
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
Eutectic Reaction ◽  
Age Hardening ◽  
Peak Hardness ◽  
Aging Behavior ◽  
Continuous Precipitation ◽  
Hardening Behavior ◽  
Average Grain Size

Our recent studies showed that continuous and cellular precipitates are covered with the whole of crystal grain in age hardable AM60 magnesium alloy cast into permanent molds, which have the average grain size of 75-85μm. Also, continuous precipitation is generated nearby grain boundary in the same alloys cast into sand molds, which have the average grain size of 138-147μm. It’s thought that permanent mold castings have the age hardening behavior of intragranular precipitation participation type that is influenced by continuous precipitates. It’s also thought that sand mold castings have the age hardening behavior of grain boundary participation type that is influenced by cellular precipitates. In this study, AM60 magnesium alloy with larger grain size was used to detect the grain size dependence of microstructure and aging behavior. In the microstructure of as-cast condition, the larger the grain size, it was shown that the none-equilibrium crystallized β phase with eutectic reaction during the solidification between liquidus and solidus temperatures becomes large-size. In the age hardening curves, the peak hardness values become higher with decreasing of grain size.

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.

Hrtem Observation of the Precipitates in Cu and Ag Added Al-Mg-Si Alloys

2013 ◽  
Vol 58 (2) ◽  
pp. 363-364
Author(s):  
M. Tokuda ◽  
K. Matsuda ◽  
T. Nagai ◽  
T. Kawabata ◽  
J. Nakamura ◽  
...  
Keyword(s):  
Hardness Test ◽  
Age Hardening ◽  
Peak Hardness ◽  
Ag Addition ◽  
Aging Period ◽  
Cu Alloy ◽  
Hrtem Observation ◽  
Aging Precipitation ◽  
Early Aging

It has been known that Cu- and Ag-added Al-1.0mass%Mg2Si alloys (Al-Mg-Si-Cu alloy and Al-Mg-Si-Ag alloy) have higher hardness and elongation than those of Al-1.0mass%Mg2Si alloy. In this study, the aging behaviour of Al-Mg-Si-Cu alloy, Al-Mg-Si-Ag alloy and (Cu+Ag)-addition Al -1.0 mass% Mg2Si alloy has been investigated by hardness test and TEM observation. The Al-Mg-Si-Cu-Ag alloy has the fastest age-hardening rate in the early aging period and the finest microstructure at the peak hardness among three alloys. Therefore the microstructure of the precipitate in Al-Mg-Si-Cu-Ag alloy has been investigated by HRTEM observation to understand the effect of Cu and Ag addition on aging precipitation.

TEM Observation of Cu and Ag Addition Al-Mg-Si Alloys

2011 ◽  
Vol 409 ◽  
pp. 81-83
Author(s):  
Momoko Tokuda ◽  
Kenji Matsuda ◽  
Takeshi Nagai ◽  
Junya Nakamura ◽  
Tokimasa Kawabata ◽  
...  
Keyword(s):  
Hardness Test ◽  
Age Hardening ◽  
Peak Hardness ◽  
Ag Addition ◽  
Aging Period ◽  
Cu Alloy ◽  
Hrtem Observation ◽  
Aging Precipitation ◽  
Early Aging

It has been known that Cu-and Ag-addition Al-1.0mass%Mg2Si alloys (Al-Mg-Si-Cu alloy and Al-Mg-Si-Ag alloy) have higher hardness and elongation than those of Al-1.0mass%Mg2Si alloy. In this study, the aging behaviour of Al-Mg-Si-Cu alloy, Al-Mg-Si-Ag alloy and (Cu+Ag)-addition Al-1.0 mass% Mg2Si alloy (Al –Mg –Si-Cu-Ag alloy) has been investigated by hardness test and TEM observation. The Al-Mg-Si-Cu-Ag alloy has the fastest age-hardening rate in the early aging period and the finest microstructure at the peak hardness among three alloys. Therefore the microstructure of the precipitate in Al–Mg–Si-Cu-Ag alloy has been investigated by HRTEM observation to understand the effect of Cu and Ag addition on aging precipitation.

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