scholarly journals Influence of Aging on Mechanical Properties of Yttria-Doped Zirconia

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 287-303 ◽  
Author(s):  
Yuta Kimura ◽  
Takuto Kushi ◽  
Atsushi Unemoto ◽  
Koji Amezawa ◽  
Tatsuya Kawada
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Aging Treatment ◽  
Resonance Method ◽  
The Other ◽  
Shear Moduli ◽  
Local Ordering ◽  
The Difference ◽  
Increasing Temperature

We evaluated the influence of aging on mechanical properties of 8% yttria-doped zirconia (8YSZ) from room temperature to 1200 K. The temperature dependence of the dynamic Young’s and shear moduli of 8YSZ with and without the aging treatment was investigated by using a resonance method. The dynamic Young’s and shear moduli of 8YSZ without the aging treatment decreased by 33% below 700 K and gradually increased at higher temperatures with increasing temperature. On the other hand, those with the aging treatments decreased by around 20% below 600 K while did not significantly change above 600 K with increasing temperature. These demonstrated the effect of aging on the dynamic Young’s and shear moduli of 8YSZ was most remarkable at intermediate temperatures (600~1000 K). Although it was suggested that the existence ratio of the metastable tetragonal phase was increased during the aging treatment, it is likely that the influence of this phase transition on the dynamic Young’s and shear moduli was not significant. It seemed that the difference in the dynamic Young’s and shear moduli of 8YSZ with and without the aging treatment at intermediate temperatures was due to the local ordering of the oxygen vacancies.

scholarly journals The principal magnetic susceptibilities of neodymium sulphate octahydrate at low temperatures

1939 ◽  
Vol 170 (941) ◽  
pp. 266-271 ◽  
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Energy Levels ◽  
Constant Factor ◽  
The Other ◽  
Crystalline Field ◽  
Cubic Symmetry ◽  
The Subject ◽  
The Difference ◽  
The One

The magnetic and other related properties of neodymium sulphate have been the subject of numerous investigations in recent years, but there is still a remarkable conflict of evidence on all the essential points. The two available determinations of the susceptibility of the powdered salt at low temperatures, those of Gorter and de Haas (1931) from 290 to 14° K and of Selwood (1933) from 343 to 83° K both fit the expression X ( T + 45) = constant over the range of temperature common to both, but the constants are not the same and the susceptibilities at room temperature differ by 11%. The fact that the two sets of results can be converted the one into the other by multiplying throughout by a constant factor suggested that the difference in the observed susceptibilities was due to some error of calibration. It could, however, also be due to the different purity of the samples examined though the explanation of the occurrence of the constant factor is then by no means obvious. From their analysis of the absorption spectrum of crystals of neodymium sulphate octahydrate Spedding and others (1937) conclude that the crystalline field around the Nd+++ ion is predominantly cubic in character since they find three energy levels at 0, 77 and 260 cm. -1 .* Calculations of the susceptibility from these levels reproduce Selwood’s value at room temperature but give no agreement with the observations-at other temperatures. On the other hand, Penney and Schlapp (1932) have shown that Gorter and de Haas’s results fit well on the curve calculated for a crystalline field of cubic symmetry and such a strength that the resultant three levels lie at 0, 238 and 834 cm. -1 , an overall spacing almost three times as great as Spedding’s.

Effect of Fast Annealing on Microstructure and Mechanical Properties of Non-Oriented Al-Si Low C Electrical Steels

2007 ◽  
Vol 560 ◽  
pp. 29-34 ◽  
Author(s):  
Emmanuel Gutiérrez C. ◽  
Armando Salinas-Rodríguez ◽  
Enrique Nava-Vázquez
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Tensile Tests ◽  
Rate Of Change ◽  
Uniaxial Tensile ◽  
Electrical Steels ◽  
Offset Yield Strength ◽  
Microstructure And Mechanical Properties ◽  
Increasing Temperature

The effects of heating rate and annealing temperature on the microstructure and mechanical properties of cold rolled Al-Si, low C non-oriented electrical steels are investigated using SEM metallography and uniaxial tensile tests. The experimental results show that short term annealing at temperatures up to 850 °C result in microstructures consisting of recrystallized ferrite grains with sizes similar to those observed in industrial semi-processed strips subjected to long term batch annealing treatments. Within the temperature range investigated, the grain size increases and the 0.2% offset yield strength decreases with increasing temperature. It was observed that the rate of change of grain size with increasing temperature increases when annealing is performed at temperatures greater than Ac1 (~870 °C). This effect is attributed to Fe3C dissolution and rapid C segregation to austenite for annealing temperatures within the ferrite+austenite phase field. This leads to faster ferrite growth and formation of pearlite when the steel is finally cooled to room temperature. The presence of pearlite at room temperature decreases the ductility of samples annealed at T > Ac1.

Effects of HIP Process on the Microstructure and Mechanical Properties of a Cast Superalloy

2017 ◽  
Vol 898 ◽  
pp. 476-479
Author(s):  
Jin Xia Yang ◽  
Yuan Sun ◽  
Dong Ling Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Room Temperature ◽  
Stress Rupture ◽  
Homogeneous Distribution ◽  
Standard Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
The Difference ◽  
Hip Process ◽  
Cast Superalloy

The effects of HIP process on microstructure and mechanical properties of IN792 cast superalloy were studied. The results showed that HIP process produced more uniform and finer cubic γ′ than standard heat treatment. The difference of the mechanical properties should be caused by the microstructure changes. HIP process leads the homogeneous distribution of γ′ at dendritic arm and interdendritic area, and improved UTS and YS of tested alloy at 550°C. However, it played no role in increasing UTS and YS at room temperature and stress-rupture lives of 760°C/662MPa and decreased stress-rupture lives of 982°C/186MPa.

Influence of aging on mechanical properties of equal channel angular pressed aluminum alloy 7075

2015 ◽  
Vol 231 (10) ◽  
pp. 1803-1811 ◽  
Author(s):  
Seyed Mahmoud Ghalehbandi ◽  
Alireza Fallahi Arezoodar ◽  
Hossein Hosseini-Toudeshky
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Subsequent Aging ◽  
Good Ductility ◽  
Angular Pressing ◽  
Aluminum Alloy 7075

Effect of aging treatment on mechanical properties of an age-hardenable aluminum alloy after equal channel angular pressing at room temperature has been investigated using hardness, stress–strain behavior and surface fractography. Aluminum alloy 7075 was pressed after solution treatment. Yield stress, ultimate stress and hardness of pressed samples have increased significantly compared with those of coarse grain, but the elongation to failure has decreased. Also the pressed specimens were subjected to aging treatment at room temperature and temperatures of 80 °C, 100 °C, 120 °C and 140 °C to obtain the optimized strength and ductility. The results indicated that post–equal channel angular pressing aging at 80 °C has resulted in the maximum strength, and natural aging has resulted in good ductility and acceptable strength. It confirmed the fact that there is a potential in obtaining high strength and good ductility in age-hardenable alloys employing severe plastic deformation and subsequent aging.

Effect of mechanical-annealing on the mechanical properties of a Zr-based bulk metallic glass

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940052
Author(s):  
P. Deng ◽  
X. C. Wang ◽  
F. Zhang ◽  
X. M. Qin ◽  
P. Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Room Temperature ◽  
Constant Pressure ◽  
Aging Treatment ◽  
Model Material ◽  
Glass Forming ◽  
Plastic Stage

The mechanical-annealing referred in this work is also named pre-strain, which is widely investigated in TRIP steel, stainless steel, magnesium alloy and aluminum alloy. In this case, we used preloading to input energy into a bulk metallic glass (BMG) to observe the changes in the structure and mechanical properties. We selected Zr[Formula: see text]Co[Formula: see text]Al[Formula: see text] BMG as a model material owning to its outstanding glass forming ability and excellent mechanical properties. The samples were kept at a constant pressure of 1900, 1700 and 1500 MPa (below the yield strength) for 40, 55 and 70 h. The study found out that the density of those samples increased after being pre-loaded. Then, the samples underwent aging treatment at room-temperature for more than 30 days after unloading. After re-compressing the samples, the results show that the yield strength and fracture strength of the samples decreased, and the amplitude of the serrated plastic flow increased during the plastic stage. Our finding might have some implications for understanding the plastic deformation of BMGs.

Current States and Development of Research on Redissolution and Reprecipitation of Nanoprecipitated Phases in Al–Cu Alloys

2019 ◽  
Vol 11 (11) ◽  
pp. 1489-1501
Author(s):  
Wenjing He ◽  
Caihe Fan ◽  
Shu Wang ◽  
Junhong Wang ◽  
Su Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
Supersaturated Solid Solution ◽  
Aluminum Matrix ◽  
Aging Treatment ◽  
Cu Alloys ◽  
The Reformation

The evolution of nanoprecipitated phases in Al–Cu alloys under severe plastic deformation (SPD) is summarized in this study. SPD at room temperature induces the precipitation of Al–Cu alloys to dissolve, leading to the reformation of supersaturated solid solution in the aluminum matrix. In the process of SPD or aging treatment after the SPD, the reprecipitated phases are precipitated from the aluminum matrix and the mechanical properties of the alloys are remarkably improved. The mechanism and system of the redissolution of the precipitation phases and the effects of redissolution and reprecipitation on the microstructure and properties of Al–Cu alloys are comprehensively analyzed. The development and future of redissolution and reprecipitation of nanoprecipitated phases in Al–Cu alloys are also described.

Effect of Nd on Microstructures and Properties of AZ31 Wrought Mg Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 301-304
Author(s):  
Wei Qiu ◽  
En Hou Han ◽  
Lu Liu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Mg Alloys ◽  
The Other ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructures And Mechanical Properties ◽  
Re Elements

Addition of RE elements to Al-containing Mg alloys can improve properties of Mg alloys at elevated temperatures. In the present investigation, hot-extruded AZ31+x%Nd. (x=0.1,0.3,0.6and1.0 wt%) wrought Mg alloy were prepared .The effects of Nd on microstructures and mechanical properties at room temperature of new alloy were investigated. The investigation found that Nd can bring about two kind of precipitation phases . One is AlNd phase, the other is AlNdMn phase, which were identified as Al11Nd3 and Al8NdMn4 by X-ray diffraction and TEM.

Preparation, Structure and Mechanical Properties of RuAl and (Ru,Ni)Al Alloys

1996 ◽  
Vol 460 ◽  
Author(s):  
A. L. R. Sabariz ◽  
G. Taylor
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Room Temperature ◽  
Binary Compound ◽  
Lattice Parameter ◽  
Al Alloys ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
Cscl Type ◽  
The Difference

ABSTRACTThe intermetallic compound, RuAl with B2 CsCl type structure, has been shown to possess room-temperature toughness and plasticity. NiAl also forms a B2 compound and it is claimed that a pseudo-binary compound, (Ru,Ni)Al, may be formed because the difference in lattice parameter between the two binary phases is slight. In this work a study has been made of the mechanical properties of some polycrystalline compounds, across the RuAl-(Ru,Ni)Al pseudo-binary, prepared from high-purity elemental powders. Compressive yield stresses were measured between room-temperature and 900°C, and the mechanisms of plastic flow are discussed in relation to the dislocation structures observed by TEM. Hot-microhardness tests were made to provide an indication of the effect of solid-solution hardening.

Thermal and Mechanical Properties of Hf Hydrides with Various Hydrogen Content

2009 ◽  
Vol 1215 ◽  
Author(s):  
Ken Kurosaki ◽  
Masato Ito ◽  
Yuki Kitano ◽  
Hiroaki Muta ◽  
Masayoshi Uno ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Vickers Hardness ◽  
Temperature Effects ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Thermal And Mechanical Properties ◽  
Shear Moduli ◽  
Delta Phase

AbstractFine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermal and mechanical properties were characterized. In the temperature range from room temperature to around 650 K, the heat capacity and thermal diffusivity of the samples were measured and the thermal conductivity was evacuated. The elastic modulus was calculated from the measured sound velocity. The Vickers hardness was measured at room temperature. Effects of CH and/or temperature on the properties of Hf hydrides were discussed. At room temperature, the thermal conductivity values of the Hf hydrides were 23 Wm−1K−1. The Young's and shear moduli and the Vickers hardness of Hf hydride decreased with increasing CH.

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