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.

Modeling the Microstructural and Yield Strength Evolution of an Age-Hardenable Al Alloy for High Temperature Applications

2016 ◽  
Vol 879 ◽  
pp. 380-385 ◽  
Author(s):  
Marco Colombo ◽  
Elisabetta Gariboldi ◽  
Paola Bassani ◽  
Mihaela Albu ◽  
Ferdinand Hofer
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Elevated Temperatures ◽  
Age Hardening ◽  
Homogeneous Distribution ◽  
Al Alloy ◽  
Physically Based ◽  
The Matrix ◽  
Physically Based Models

The mechanical properties of Al alloys are strongly affected by their microstructure: the size and shape of precipitates, their homogeneous distribution and their coherency with the matrix are of primary importance for an effective strengthening of the alloys at room and elevated temperatures. Physically-based models are powerful tools to predict the influence of the mentioned parameters on the mechanical properties of the alloy after age hardening, and also to predict the effect of high temperature service conditions on microstructure evolution. Scope of this work is to model the dimensional kinetic evolution of plate shaped precipitates of an Al-based alloy during aging and after different overaging times at elevated temperature, and use these results to estimate the alloy yield strength. The alloy strengthening response is due to three terms, linearly summed: the intrinsic strength of Aluminum, the contribution from solute in solid solution and the contribution arising from precipitates. The consistency of the model is verified with experimental data obtained from a 2014 Al alloy.

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

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.

scholarly journals The Effect of Reinforcement Ratio on the Composite Structure and Mechanical Properties in Al-MgO Composites Produced by the Melt Stirring Method

2011 ◽  
Vol 20 (4) ◽  
pp. 096369351102000 ◽  
Author(s):  
Recep Çalin ◽  
Pul Muharrem ◽  
Ramazan Çitak ◽  
Ulvi Şeker
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Metal Matrix ◽  
Vertical Direction ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
Liquid Matrix ◽  
The Matrix ◽  
Micro Structures ◽  
Scanning Electron

In this study, Al- MgO metal matrix composites (MMC) were produced with 5 %, 10 % and 15 % reinforcement- volume (R-V) ratios by the melt stirring method. In the production of composites 99.5 % pure Al was used as the matrix and MgO powders with the particle size of −105 μm were used as the reinforcement. For every R-V ratio; stirring was made at 500 rev/min at 750°C liquid matrix temperature for 4 minutes and the samples were cooled under normal atmosphere. Then hardness and fracture strengths of the samples were determined and their micro structures were evaluated by using Scanning Electron Microscope (SEM). In general, it was observed that the reinforcement exhibited a homogeneous distribution in horizontal direction. But there is a slight inhomogeneity in vertical direction. It was determined that the increase in the R-V ratio increased the porosity and also the hardness. As for the fracture strength, the highest strength was obtained with the 5 % MgO reinforced sample.

Characterization of Precipitation Evolution in a Zn-Added Al-Mg-Si-Cu Alloy during Artificial Aging at 170 °C

2018 ◽  
Vol 941 ◽  
pp. 961-966
Author(s):  
Shang Zhu ◽  
Zhi Hui Li ◽  
Li Zhen Yan ◽  
Xi Wu Li ◽  
Shu Hui Huang ◽  
...  
Keyword(s):  
Artificial Aging ◽  
Age Hardening ◽  
Peak Hardness ◽  
Aging Condition ◽  
Β Phase ◽  
Cu Alloy ◽  
Zn Concentration ◽  
The Matrix ◽  
Small Clusters

A Zn-added Al-Mg-Si-Cu alloy during aging at 170 °C up to 34 h exhibits an interesting age-hardening effect. Small clusters, enriched in Mg and Si, are present in the sample after 0.25 h aging. The β′′ phase is dominant with the peak hardness of 135 HV after aging of 8 h. A decrease in hardness of the alloy occurs with the aging time increasing to 34 h, due to the coarsening of β′′ phase. It is also found that the Cu-containing L phase co-exists with the β′′ phase at this aging condition. The quantitative solute concentrations of the matrix show that the formation of clusters is consistent with the slight lower contents of Mg, Si and Cu compared with the alloy chemical composition, and the present of β′′ and L phase is associated with the further partitioning of Mg, Si and Cu from the Al matrix into the precipitates. No Zn-rich clusters and precipitates are observed and the Zn concentration in matrix has no significant change during aging for up to 34 h. This result means that the major of Zn remains in the matrix as aging continues.

Preparation and Mechanical Properties of Nano-SiCp/Mg Composites by Ultrasonic Dispersion

2010 ◽  
Vol 150-151 ◽  
pp. 792-795 ◽  
Author(s):  
Hong Yan ◽  
Zhi Hu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Ultrasonic Method ◽  
Fracture Morphology ◽  
Dispersion Strengthening ◽  
Ultrasonic Dispersion ◽  
Sic Nanoparticles ◽  
The Matrix ◽  
Dislocation Strengthening ◽  
Magnesium Composites

SiC nanoparticles reinforced AZ61 magnesium composites were fabricated by Ultrasonic method. The distribution of nanoparticles in the matrix and the fracture morphology of the composites were observed by SEM, and the mechanical properties of the composites were tested at room temperature. Experimental shows that SiC nanoparticles were dispersed well in the matrix with the pretreatment method. Compared with the matrix, the tensile strength and hardness of the composites were improved respectively. Meanwhile, the ductility of the composites didn’t be obviously decreased. The enhancement function of nano composites was predicted with the dislocation strengthening and Orowan dispersion strengthening mechanisms. The predicted results coincided well with experimental ones.

scholarly journals Effect of Processing Parameters on the Mechanical Properties of Heavy Section Ductile Iron

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Mohamed Mahmoud Mourad ◽  
Shimaa El-Hadad ◽  
Mervat Mohamed Ibrahim ◽  
Adel Abdelmonem Nofal
Keyword(s):  
Mechanical Properties ◽  
Ductile Iron ◽  
Processing Parameters ◽  
Ductile Cast Iron ◽  
Heavy Section ◽  
The Matrix ◽  
Cast Alloys ◽  
One Step ◽  
Inoculation Procedure ◽  
Inoculation Treatment

The main objective of the current work is to investigate the influence of different inoculation conditions on the microstructure and mechanical properties of heavy section ductile iron (DI) castings. Inoculation treatment was done via one step and double step treatments with different amounts of inoculants. The mechanical properties of the fabricated samples were evaluated. The best inoculation procedure in terms of graphite nodules characteristics and mechanical properties was double inoculation with 0.8% inoculants added at first and 0.2% in the late inoculation step. The presence of Sb in one of the cast alloys controlled the growth of graphite nodules in these heavy section ductile iron castings; however low impact toughness was recorded. The matrix structure of ductile cast iron showed a significant influence not only on the strength and impact properties but also on the fracture mode during testing.

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 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.

Effects of Zr on Microstructures and Properties of a β Matrix Mg-13Li-3Al-0.7Zr Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 155-160 ◽  
Author(s):  
Bin Chen ◽  
Lin Ping Feng ◽  
Tie Tao Zhou ◽  
Pei Ying Liu ◽  
Huan Xi Li
Keyword(s):  
Tensile Properties ◽  
Grain Refinement ◽  
Age Hardening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure And Properties ◽  
Heat Treated ◽  
The Matrix ◽  
Cold Rolled ◽  
Zr Alloy

The effects of Al, Zr additions on the microstructure and properties of a β matrix Mg-Li-Al-Zr alloy of hot forged, cold rolled and heat- treated states have been systematically investigated. The tensile properties of the alloy was tested, and microstructure was studied by X-ray diffraction and SEM methods. The results showed that the addition of zirconium in the aluminum containing Mg-Li alloy was effective for grain refinement. The alloy containing zirconium of rolled state exhibited higher strength and satisfied ductility compared with the alloy without zirconium. The existence of zirconium in the alloy was mainly in the form of Al-Zr compounds of Al2Zr andAl3Zr. The reason for less age-hardening effect may be caused by the capture of aluminum by zirconium and as a consequent by the lake of aluminum in the matrix.

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