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

Effects of Gadolinium on Aging Behavior and Mechanical Properties of Mg-5Y-3Nd-Zr Alloy

2011 ◽  
Vol 295-297 ◽  
pp. 1183-1187
Author(s):  
Li Dong Wang ◽  
Cheng Yao Xing ◽  
Xiu Li Hou ◽  
Yao Ming Wu ◽  
Jian Fei Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Morphology ◽  
Age Hardening ◽  
Peak Hardness ◽  
Homogeneous Distribution ◽  
Aging Behavior ◽  
The Matrix ◽  
Cast Alloys ◽  
Mould Casting ◽  
Zr Alloy

Mg-5Y-3Nd-Zr-xGd (x=0 and 4 wt.%) alloys were prepared by metal mould casting, and aging behavior, mechanical properties and fracture morphology were investigated. The result shows that after T6 treatment, the massive eutectic phase in as-cast alloys dissolved and finer Mg5RE phase precipitated dispersively in the matrix, and mechanical properties were improved simultaneously. Mg-5Y-3Nd-4Gd-Zr alloy exhibits good age hardening behavior and the peak hardness is about 20% higher than the Gd-free alloy. Gd addition can significantly improve mechanical properties of the alloy especially at the elevated temperature. The ultimate tensile strength and yield strength of Mg-5Y-3Nd-4Gd-Zr alloy at 250°C, with the value of 276 and 168 MPa, respectively, are over 20% higher than those of the Gd-free alloy. It is mainly attributed to the increase and homogeneous distribution of the fine heat-resistant Mg5RE precipitate in the matrix.

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.

Effect of Heat-Treatment and Reinforcement With Silicon Carbide on the Microstructure and Mechanical Properties of AlFeVSi Alloy

2007 ◽  
Author(s):  
M. Arhami ◽  
F. Sarioglu ◽  
A. Kalkanli
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Age Hardening ◽  
Microstructure And Mechanical Properties ◽  
Sic Particles ◽  
Aging Response ◽  
The Matrix ◽  
Peak Aged ◽  
Aging Kinetics ◽  
Fe Intermetallics

The aging response of Al-Fe-V-Si composite was compared with the un-reinforced alloy. The effects of solutionizing time, alloying element and SiC reinforcement on the age hardening response, microstructure and mechanical properties of these alloy and its composites was also investigated. The study was performed by T6 heat treatment at three different solutionizing times. Room temperature tensile testing was conducted for peak aged specimens to determine the effect of this heat treatment on the strength of squeezed cast un-reinforced and reinforced Al-Fe-V-Si alloy with SiC particles. The presence of SiC particles accelerated the aging kinetics of the composites compared to the unreinforced alloys. The time to reach peak age hardness was decreased by addition of SiCp. Mainly two different Fe-intermetallics; small α-Al7(Fe, V)3Si and large β-Al18Fe11Si phases were present in the system studied. The fracture surfaces of composites revealed decohesion of SiC particles from the matrix and cracking of needle like-β intermetallics was observed.

scholarly journals Effects of Gd, Y Content on the Microstructure and Mechanical Properties of Mg-Gd-Y-Nd-Zr Alloy

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 790 ◽  
Author(s):  
Changping Tang ◽  
Kai Wu ◽  
Wenhui Liu ◽  
Di Feng ◽  
Xuezhao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Solution Treatment ◽  
Age Hardening ◽  
Uniaxial Tensile ◽  
Microstructure And Mechanical Properties ◽  
Shaped Particle ◽  
Zr Alloy ◽  
Non Equilibrium

The effects of Gd, Y content on the microstructure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy were investigated using hardness measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and uniaxial tensile testing. The results indicate that the alloys in as-cast condition mainly consist of α-Mg matrix and non-equilibrium eutectic Mg5.05RE (RE = Gd, Y, Nd). After solution treatment, the non-equilibrium eutectics dissolved into the matrix but some block shaped RE-rich particles were left at the grain boundaries and within grains. These particles are especially Y-rich and deteriorate the mechanical properties of the alloys. Both the compositions of the eutectic and the block shaped particle were independent of the total Gd, Y content of the alloys, but the number of the particles increases as the total Gd, Y content increases. The ultimate tensile strength increases as the total Gd, Y content decreases. A Mg-5.56Gd-3.38Y-1.11Nd-0.48Zr alloy with the highest ultimate tensile strength of 280 MPa and an elongation of 1.3% was fabricated. The high strength is attributed to the age hardening behavior and the decrease in block shaped particles.

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.

Investigation on the Microstructure and Mechanical Properties of Hot Forged Mg−8Gd−2Y−1Nd−0.3Zn−0.6Zr Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1598-1602 ◽  
Author(s):  
Xiu Li Hou ◽  
Zhan Yi Cao ◽  
Li Dong Wang ◽  
Li Min Wang
Keyword(s):  
Mechanical Properties ◽  
Large Strain ◽  
Hot Forging ◽  
Tensile Tests ◽  
Age Hardening ◽  
Secondary Phases ◽  
Ageing Treatment ◽  
Size Refinement ◽  
Microstructure And Mechanical Properties ◽  
Peak Aged

The influences of hot forging and ageing treatment on the microstructure and mechanical properties of Mg−8Gd−2Y−1Nd−0.3Zn−0.6Zr (wt.%) alloy have been investigated. The results showed that the grains were significantly refined after hot forging. And the secondary phases in this alloy i.e. Mg5(Gd1-x-yNdxYy) and Mg24(Y1-x-yGdxNdy)5phases were fragmented to small particles due to the large strain during hot forging. Tensile tests revealed that mechanical properties were improved due to grain size refinement. Moreover, the as-forged alloy exhibited remarkable age-hardening response and mechanical properties were further improved by ageing treatment. The ultimate tensile strength, yield strength and elongation of the peak-aged (T5) alloy are 286 MPa, 245 MPa and 5.6 % at room temperature, and 211 MPa, 103 MPa and 19.4 % at 300°C, respectively.

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.

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