scholarly journals Age-Induced Precipitation and Hardening Behavior of Ni3Al Intermetallic Alloys Containing Vanadium

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 160 ◽  
Author(s):  
Satoshi Semboshi ◽  
Ryosuke Sasaki ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi
Keyword(s):  
Testing Temperature ◽  
Age Hardening ◽  
Intermetallic Alloys ◽  
Hardening Behavior ◽  
Aging Period ◽  
Subsequent Decrease ◽  
Peak Aged ◽  
Ni3al Intermetallic ◽  
L12 Structure ◽  
Fcc Structure

L12-type Ni3Al alloys containing vanadium are potential candidates for solid-solution and age-hardenable alloy systems, according to the Ni3Al-Ni3V pseudo-binary phase diagram. Therefore, herein, variations in the microstructure and mechanical properties of Ni-13 at.% Al-12 at.% V-50 ppm B alloy during isothermal aging were investigated. Alloy specimens were solution-treated at 1323 K for 48 h, quenched in water, and aged at 1073 K to 1173 K. The quenched specimens exhibited a single phase of Ni3Al (L12 structure derived from Al (fcc) structure), while in the aged specimens, numerous fine disk-shaped precipitates identified as Ni3V (D022 structure from orthorhombic structure) were formed on {001} planes of the Ni3Al matrix. The size of the disk-shaped Ni3V precipitates increased gradually with increasing aging period. The hardness and strength of the specimens increased initially during aging at 1073 K to 1173 K, reached a maximum, followed by a subsequent decrease. The age-hardening behavior observed for the specimens can be explained in terms of precipitation of the fine disk-shaped Ni3V precipitates in the Ni3Al matrix. Furthermore, the peak-aged specimens exhibited an increase in yield strength with increasing testing temperature, similar to other L12-type intermetallic alloys.

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.

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.

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.

Effect of Zn/Mg on Age Hardening Behavior in 7000 System Al Alloys

2014 ◽  
Vol 922 ◽  
pp. 549-552
Author(s):  
Masatomo Nishi ◽  
Naoya Miura ◽  
Katsumi Watanabe ◽  
Susumu Ikeno ◽  
Tomoo Yoshida ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Tensile Test ◽  
High Strength ◽  
Hardness Measurement ◽  
Age Hardening ◽  
Number Density ◽  
Aged Condition ◽  
Hardening Behavior ◽  
Peak Aged Condition ◽  
Peak Aged

7000 System Al has been known as one of the aluminum alloys with the good age hardening ability and the high strength among commercial aluminum alloys. [1]In this study, hardness measurement, tensile test, SEM observation and TEM observation have been performed in order to understand the effect of Zn/Mg ratio on age hardening behaviour in Al-Zn-Mg alloys . It can be seen from hardness measurement that the alloy containing higher Zn and Mg contents became hard. Tensile test was performed for the samples of peak aged condition. It can been seen that the alloy containing higher Zn and Mg increases the tensile strength of the alloy though decrease of the elongation were observed a typical intergranular fracture. TEM observation was performed for peak aged samples. The size of precipitates became finer and the number density increased with increasing Zn and Mg contents.

scholarly journals Relationship between mechanical properties and age-hardening behavior around grain boundaries of Al-Mg-Si alloy

2020 ◽  
Vol 326 ◽  
pp. 03002
Author(s):  
Takuya Hashimoto ◽  
Ken-ichi Ikeda ◽  
Seiji Miura
Keyword(s):  
Mechanical Properties ◽  
Rotation Angle ◽  
Coincident Site Lattice ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Site Lattice ◽  
Hardening Behavior ◽  
Aging Precipitation ◽  
Peak Aged ◽  
Electron Back Scattered Diffraction

Nanoindentation tests were conducted near the grain boundary (GB) of the Al-Mg-Si alloy, and the influence of GB character on the aging precipitation behavior and the mechanical properties was confirmed. After obtaining the GB characters by electron back scattered diffraction (EBSD) analysis, nanoindentation tests were carried out on under-aged, peak-aged, and over-aged samples. And then, the indentation areas were observed by back scattered electrons imaging (BSE) in order to identify indentation positions with respect to the GB. In this study, for the GB character, focusing on the rotation angle, the high-angle GB (HAGB) and the low-angle GB (LAGB) were selected. In addition, coincident site lattice GBs (CSL) were selected as the special GB. In the 180°C under-aged samples, the nano-hardness near GB is higher than that far from GB, while 180°C peak-aged samples, the nano-hardness is lower than that far from GB. Then the range near the GB where the hardness changes was larger at HAGB than at LAGB and CSL3. This suggests that the GB character affects the aging precipitation behavior and mechanical properties.

The Effect of Y on Aging Response and Mechanical Properties of Mg-Ho-Zr Alloys

2011 ◽  
Vol 704-705 ◽  
pp. 546-551
Author(s):  
Bao Zhong Liu ◽  
Jiao Jiao Liu ◽  
Jian Li Wang ◽  
Bao Qing Zhang ◽  
Zhi Zhang
Keyword(s):  
Mechanical Properties ◽  
Age Hardening ◽  
Stable Phase ◽  
Hardening Behavior ◽  
Aging Response ◽  
Cast Alloys ◽  
Peak Aged ◽  
Aged State ◽  
Alloy Microstructure ◽  
Zr Alloy

Mg-10Ho-0.6Zr alloys with different amount of Y additions are prepared by metal mould casting method. The effects of Y content on microstructure, age hardening behavior and mechanical properties are investigated. Results show that all the as-cast Mg-10Ho-xY-0.6Zr alloys are mainly comprised of α-Mg matrix and Mg24(Ho,Y)5phase. With increasing Y content, grain size of the as-cast alloys is reduced. Age hardening response, Vickers hardness and mechanical properties are improved with the addition of Y. The maximum ultimate tensile strength (UTS) and yield strength (YS) are obtained in Mg-10Ho-3Y-0.6Zr alloy at peak-aged state, and the values are 215 MPa, 158 MPa at room temperature, and 144 MPa, 126 MPa at 250 °C, respectively. The improvement of the UTS is mainly attributed to the fine distributed quadrate-like β stable phase. Key words: Mg-Ho-Y-Zr alloy; Microstructure; Age hardening behavior; Mechanical properties

Precipitation in Al-Li-Cu Alloys

1981 ◽  
Vol 39 ◽  
pp. 44-45
Author(s):  
J. E. O'Neal ◽  
K. K. Sankaran
Keyword(s):  
Electron Microscopy ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Zone Formation ◽  
Specific Strength ◽  
Hardening Behavior ◽  
Cu Alloys ◽  
High Specific Strength ◽  
Transmission Electron ◽  
Structural Applications

Al-Li-Cu alloys combine high specific strength and high specific modulus and are potential candidates for aircraft structural applications. As part of an effort to optimize Al-Li-Cu alloys for specific applications, precipitation in these alloys was studied for a range of compositions, and the mechanical behavior was correlated with the microstructures.Alloys with nominal compositions of Al-4Cu-2Li-0.2Zr, Al-2.5Cu-2.5Li-0.2Zr, and Al-l.5Cu-2.5Li-0.5Mn were argon-atomized into powder at solidification rates ≈ 103°C/s. Powders were consolidated into bar stock by vacuum pressing and extruding at 400°C. Alloy specimens were solution annealed at 530°C and aged at temperatures up to 250°C, and the resultant precipitation was studied by transmission electron microscopy (TEM).The low-temperature (≲100°C) precipitation behavior of the Al-4Cu-2Li-0.2Zr alloy is a combination of the separate precipitation behaviors of Al-Cu and Al-Li alloys. The age-hardening behavior at these temperatures is characteristic of Guinier-Preston (GP) zone formation, with additional strengthening resulting from the coherent precipitation of δ’ (Al3Li, Ll2 structure), the presence of which is revealed by the selected-area diffraction pattern (SADP) shown in Figure la.

Effects of Fe Addition on Rolling and Age-Hardening Behavior in Al–Si–Mg Alloys

2017 ◽  
Vol 17 (6) ◽  
pp. 4165-4168
Author(s):  
DaeHwan Kim ◽  
JaeHwang Kim ◽  
HyeonTaek Son ◽  
KeeDo Woo
Keyword(s):  
Mg Alloys ◽  
Age Hardening ◽  
Hardening Behavior ◽  
Fe Addition

Asymmetric cryorolling of AA6061 Al alloy: Strain distribution, texture and age hardening behavior

2018 ◽  
Vol 736 ◽  
pp. 53-60 ◽  
Author(s):  
Danielle Cristina Camilo Magalhães ◽  
Andrea Madeira Kliauga ◽  
Maurizio Ferrante ◽  
Vitor Luiz Sordi
Keyword(s):  
Strain Distribution ◽  
Age Hardening ◽  
Al Alloy ◽  
Hardening Behavior
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