SPRING-BACK CHARACTERISTICS OF GRAIN-REFINED MAGNESIUM ALLOY ZK60 SHEET

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6076-6081 ◽  
Author(s):  
SEONG-HOON KANG ◽  
YOUNG-SEON LEE ◽  
JUNG-HWAN LEE
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Testing Temperature ◽  
The Other ◽  
Bending Test ◽  
Spring Back ◽  
Bending Tests ◽  
Grain Sizes ◽  
Before And After

In this work, the effect of grain size on the spring-back characteristic was investigated by carrying out air-bending test using magnesium alloy ZK60 sheet with thickness of 0.5 mm at the various temperatures from room temperature to 300 °C. The angles of the bent specimen before and after unloading were measured in order to quantify spring-back amount. It was found out from the bending tests that when the specimens with grain sizes of 14.66 and 60.71 µm were bent by 90°, the amount of spring-back was relatively small at the testing temperature range and was in the range between -2.5° and 2.5°. On the other hand, the spring-back amount dramatically increased at room temperature and phenomenon of spring-go was observed at high temperature when the specimen with submicro grain size of 0.98 µm was bent by 90°. From this finding, it was confirmed that the different spring-back characteristics according to the grain size takes place and thus the grain size of material is one of the important factors which have an effect on the spring-back.

Newly Developed Heat Resistant Magnesium Alloy by Thixomolding®

2005 ◽  
Vol 488-489 ◽  
pp. 287-290 ◽  
Author(s):  
Tadayoshi Tsukeda ◽  
Ken Saito ◽  
Mayumi Suzuki ◽  
Junichi Koike ◽  
Kouichi Maruyama
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Die Casting ◽  
The Other ◽  
Heat Resistant ◽  
Higher Temperature ◽  
Better Than

We compared the newly developed heat resistant magnesium alloy with conventional ones by Thixomolding® and aluminum alloy by die casting. Tensile properties at elevated temperatures of AXEJ6310 were equal to those of ADC12. In particular, elongation tendency of AXEJ6310 at higher temperature was better than those of the other alloys. Creep resistance of AXEJ6310 was larger than that of AE42 by almost 3 orders and smaller than that of ADC12 by almost 2 orders of magnitude. Fatigue limits at room temperature and 423K of AXEJ6310 was superior among conventional magnesium alloys.

scholarly journals Is Superplasticity in the Future of Nanophase Materials?

1990 ◽  
Vol 196 ◽  
Author(s):  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Atomic Clusters ◽  
Diffusional Creep ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Nanophase Materials ◽  
Boundary Sliding

ABSTRACTThe ultrafine grain sizes and high diffusivities in nanophase materials assembled from atomic clusters suggest that these materials may have a strong tendency toward superplastic mechanical behavior. Both small grain size and enhanced diffusivity can be expected to lead to increased diffusional creep rates as well as to a significantly greater propensity for grain boundary sliding. Recent mechanical properties measurements at room temperature on nanophase Cu, Pd, and TiO2, however, give no indications of superplasticity. Nonetheless, significant ductility has been clearly demonstrated in these studies of both nanophase ceramics and metals. The synthesis of cluster-assembled nanophase materials is described and the salient features of what is known of their structure and mechanical properties is reviewed. Finally, the answer to the question posed in the title is addressed.

Fatigue Behavior of Age-Hardening Cu-6Ni-1.5Si Alloys with Different Grain Sizes

2021 ◽  
Vol 1016 ◽  
pp. 125-131
Author(s):  
Masahiro Goto ◽  
T. Yamamoto ◽  
S.Z. Han ◽  
J. Kitamura ◽  
J.H. Ahn ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Fatigue Strength ◽  
Solution Heat Treatment ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
The Other ◽  
Age Hardening ◽  
Grain Sizes ◽  
Thermomechanical Processes

On the thermomechanical treatments of Cu-Ni-Si alloy, cold-rolling (CR) before solution heat treatment (SHT) is commonly conducted to eliminate defects in a casting slab. In addition, a rolling is applied to reduce/adjust the thickness of casting slab before SHT. In a heavily deformed microstructure by CR, on the other hand, grain growth during a heating in SHT is likely to occur as the result of recrystallization. In general, tensile strength and fatigue strength tend to decrease with an increase in the grain size. However, the effect of difference in grain sizes produced by with and without CR before SHT on the fatigue strength is unclear. In the present study, fatigue tests of Cu-6Ni-Si alloy smooth specimens with a grain fabricated through different thermomechanical processes were conducted. The fatigue behavior of Cu-Ni-Si alloy was discussed.

scholarly journals Performance of Flexible Chemoresistive Gas Sensors after Having Undergone Automated Bending Tests

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5190 ◽  
Author(s):  
Miriam Alvarado ◽  
Silvia De La Flor ◽  
Eduard Llobet ◽  
Alfonso Romero ◽  
José Luis Ramírez
Keyword(s):  
Metal Oxide ◽  
Gas Sensing ◽  
Flexible Substrate ◽  
Test Procedure ◽  
Chemical Vapor ◽  
Bending Test ◽  
Bending Tests ◽  
Ag Electrodes ◽  
Different Types ◽  
Before And After

Many sensors are developed over flexible substrates to be used as wearables, which does not guarantee that they will actually withstand being bent. This work evaluates the gas sensing performance of metal oxide devices of three different types, before and after having undergone automated, repetitive bending tests. These tests were aimed at demonstrating that the fabricated sensors were actually flexible, which cannot be taken for granted beforehand. The active layer in these sensors consisted of WO3 nanowires (NWs) grown directly over a Kapton foil by means of the aerosol-assisted chemical vapor deposition. Their response to different H2 concentrations was measured at first. Then, they were cyclically bent, and finally, their response to H2 was measured again. Sensors based on pristine WO3-NWs over Ag electrodes and on Pd-decorated NWs over Au electrodes maintained their performance after having been bent. Ag electrodes covered with Pd-decorated NWs became fragile and lost their usefulness. To summarize, two different types of truly flexible metal oxide gas sensor were fabricated, whereas a third one was not flexible, despite being grown over a flexible substrate following the same method. Finally, we recommend that one standard bending test procedure should be established to clearly determine the flexibility of a sensor considering its intended application.

Effect of Trace Boron Addition on the Microstructure and Tensile Elongation of Ti2AlNb-Based Orthorhombic Titanium Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1439-1444
Author(s):  
Masuo Hagiwara ◽  
Tomoyuki Kitaura
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Tensile Elongation ◽  
Boron Addition ◽  
Grain Sizes ◽  
Solution Treated Condition ◽  
Room Temperature Ductility ◽  
Solution Treated ◽  
Treated Condition ◽  
Orthorhombic Titanium

The grain sizes of two kinds of orthorhombic alloys, namely (O+B2) Ti-22Al-11Nb-2Mo -1Fe and (O+2) Ti-27.5Al-13Nb have been successfully reduced by the addition of trace boron (B) (less than 0.12 wt.%). For example, the grain size in the B2 solution-treated condition was reduced from 1 mm to 80 m by the addition of 0.05% B for both alloys. The tensile elongation of Ti-22Al-11Nb-2Mo-1Fe at room temperature and 650C was increased from 0.3% to 4.3%, and from 8.2% to 30.3%, respectively, by the addition of 0.10% B. Ti-27.5Al-13Nb also showed an improved room temperature ductility by the minor B addition.

Dielectric Properties of Nanograined BaTiO3 Ceramics Fabricated by Aerosol Deposition Method

2011 ◽  
Vol 485 ◽  
pp. 183-186 ◽  
Author(s):  
Tsutomu Furuta ◽  
Saki Hatta ◽  
Yoichi Kigoshi ◽  
Takuya Hoshina ◽  
Hiroaki Takeda ◽  
...  
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Aerosol Deposition ◽  
Dielectric Measurement ◽  
Deposition Method ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Aerosol Deposition Method ◽  
Polarization Electric Field

Freestanding BaTiO3 ceramics films were fabricated using the aerosol deposition (AD) method and the size effect of nanograined BaTiO3 ceramics was demonstrated. Dense BaTiO3 thick film fabricated by the AD method was crystallized and detached from substrate by an annealing treatment at 600 °C, and then the grain size was controlled by a reannealing treatment at various temperatures. As a result, freestanding BaTiO3 thick films with various grain sizes from 24 to 170 nm were successfully obtained. Polarization–electric field (P–E) measurement revealed that BaTiO3 ceramics with grain sizes of more than 58 nm showed ferroelectricity, whereas BaTiO3 ceramics with an average grain size of 24 nm showed paraelectricity at room temperature. Dielectric measurement indicated that the permittivity decreased with decreasing grain size in the range of 170 to 24 nm.

Microstructure and Mechanical Properties of Magnesium Alloy AZ61with 1%Sn Addition

2014 ◽  
Vol 881-883 ◽  
pp. 1396-1399
Author(s):  
Chen Jun ◽  
Quan An Li
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Az61 Alloy ◽  
Microstructure And Mechanical Properties ◽  
Microstructure Morphology

The microstructure and mechanical properties of magnesium alloy AZ61wtih1% Sn addition has been studied in this paper. The results show that the addition of 1% Sn can refine the grain size and improve the microstructure morphology of β-Mg17Al12 phase. The addition of Sn can cause the formation of Mg2Sn phase in AZ61 alloy, which can effectively enhance the mechanical properties of magnesium alloy AZ61 at room temperature and 150°C.

Microstructure Prediction by Finite Element Analysis during Hot Rolling of Magnesium Alloy Sheets

2015 ◽  
Vol 661 ◽  
pp. 105-112
Author(s):  
Yeong Maw Hwang ◽  
Tso Lun Yeh
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Optimal Conditions ◽  
Compression Tests ◽  
Element Analysis ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Microstructure Prediction ◽  
Alloy Microstructure ◽  
The Relationship

Material’s plastic deformation by hot forming processes can be used to make the materials generate dynamic recrystallization (DRX) and fine grains and accordingly products with more excellent mechanical properties, such as higher strength and larger elongation can be obtained. In this study, compression tests and water quenching are conducted to obtain the flow stress of the materials and the grain size after DRX. Through the regression analysis, prediction equations for the magnesium alloy microstructure were established. Simulations with different rolling parameters are conducted to find out the relationship between the DRX fractions or grain sizes of the rolled products and the rolling parameters. The simulation results show that rolling temperature of 400°C and thickness reduction of 50% are the optimal conditions. An average grain size of 0.204μm-0.206μm in the microstructure is obtained and the strength and formability of ZK60 magnesium alloys can be improved.

Anelastic Behavior of Nanocrystalline Fe-Cr Alloy Obtained by Mechanical Alloying

2010 ◽  
Vol 146-147 ◽  
pp. 780-784
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
H. Yang
Keyword(s):  
Internal Friction ◽  
Mechanical Alloying ◽  
Dynamic Modulus ◽  
Room Temperature ◽  
Milling Time ◽  
Grain Sizes ◽  
Free Decay ◽  
Before And After ◽  
Anelastic Behavior ◽  
Increasing Temperature

Anelastic behavior of nanocrystalline Fe-17 wt.%Cr alloy obtained by mechanical alloying was investigated using a multifunctional internal friction apparatus. Internal friction (Q-1) and relative dynamic modulus (f2) have been measured as a function of temperature by free-decay method from room temperature to 400oC for the ball-milled Fe-17 wt.%Cr alloy The specimens with different milling time were examined by XRD to determine the solid solubility of Fe and Cr atoms and detect the lattice strain of the compacted specimen before and after annealing. TEM observation was employed to obtain further information about the morphology and microstructure, especially crystalline size, of the milled Fe and Cr mixture powders. It has been suggested that the anelastic behavior of ball-milled nanocrystalline Fe-17 wt.%Cr alloy origins from the viscoelastic sliding at the interfaces resulting from the thermally-activating process. The damping increasing of the specimen with smaller grain sizes is larger than that of the specimen with larger grain sizes with increasing temperature since the former contains more interfaces. The increase in the relative dynamic modulus is attributed to the structural reordering with the lowering of lattice micro-strain that is produced during milling when temperature is over 300oC.

scholarly journals Tensile Strength and Creep Resistance in Nanocrystalline Cu, Pd and Ag

1990 ◽  
Vol 206 ◽  
Author(s):  
G. W. Nieman ◽  
J. R. Weertman ◽  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Yield Strength ◽  
Creep Resistance ◽  
Room Temperature ◽  
True Strain ◽  
Constant Load ◽  
Creep Tests ◽  
Grain Sizes

ABSTRACTMeasurements of tensile strength and creep resistance have been made on bulk samples of nanocrystalline Cu, Pd and Ag consolidated from powders by cold compaction. Samples of Cu-Cu2O have also been tested. Yield strength for samples with mean grain sizes of 5–80 nm and bulk densities on the order of 95% of theoretical density are increased 2–5 times over that measured in pure, annealed samples of the same composition with micrometer grain sizes. Ductility in the nanocrystalline Cu has exceeded 6% true strain, however, nanocrystalline Pd samples were much less ductile. Constant load creep tests performed at room temperature at stresses of >100 MPa indicate logarithmic creep. The mechanical properties results are interpreted to be due to grain size-related strengthening and processing flaw-related weakening.

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