scholarly journals Highly ductile amorphous oxide at room temperature and high strain rate

Science ◽  
2019 ◽  
Vol 366 (6467) ◽  
pp. 864-869 ◽  
Author(s):  
Erkka J. Frankberg ◽  
Janne Kalikka ◽  
Francisco García Ferré ◽  
Lucile Joly-Pottuz ◽  
Turkka Salminen ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Room Temperature ◽  
High Strain ◽  
Total Elongation ◽  
Modern World ◽  
Mechanical Resistance ◽  
Oxide Glasses ◽  
Amorphous Oxide ◽  
Damage Tolerant

Oxide glasses are an integral part of the modern world, but their usefulness can be limited by their characteristic brittleness at room temperature. We show that amorphous aluminum oxide can permanently deform without fracture at room temperature and high strain rate by a viscous creep mechanism. These thin-films can reach flow stress at room temperature and can flow plastically up to a total elongation of 100%, provided that the material is dense and free of geometrical flaws. Our study demonstrates a much higher ductility for an amorphous oxide at low temperature than previous observations. This discovery may facilitate the realization of damage-tolerant glass materials that contribute in new ways, with the potential to improve the mechanical resistance and reliability of applications such as electronic devices and batteries.

scholarly journals High Strain Rate Tensile Properties of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (4) ◽  
pp. 361-368 ◽  
Author(s):  
R. L. Klueh ◽  
R. E. Oakes
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
High Strain ◽  
Total Elongation ◽  
Major Effect ◽  
Dynamic Strain

The high strain rate tensile properties of annealed 2 1/4 Cr-1 Mo steel were determined and the tensile behavior from 25 to 566°C and strain rates of 2.67 × 10−6 to 144/s were described. Above 0.1/s at 25°C, both the yield stress and the ultimate tensile strength increased rapidly with increasing strain rate. As the temperature was increased, a dynamic strain aging peak appeared in the ultimate tensile strength-temperature curves. The peak height was a maximum at about 350°C and 2.67 × 10−6/s. With increasing strain rate, a peak of decreased height occurred at progressively higher temperatures. The major effect of strain rate on ductility occurred at elevated temperatures, where a decrease in strain rate caused an increase in total elongation and reduction in area.

Effect of Strain Rate on Cavity Closure during Compression between Flat Platens Using Superplastic Tin-Lead Alloy

2012 ◽  
Vol 510-511 ◽  
pp. 436-442
Author(s):  
A.I.O. Zaid ◽  
M.M. Al-Tamimi
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Room Temperature ◽  
High Strain ◽  
Large Strain ◽  
Outer Diameter ◽  
Lead Alloy ◽  
Engineering Materials ◽  
Cavity Closure ◽  
Reduction Percentage

Superplasticity is a feature of a material or alloy which allows the material to deform plastically to an extremely large strain at low values of stress under certain loading conditions of strain rate and temperature. Eutectic tin-lead alloy is a practical material for research investigations as it possesses a superplastic behavior at room temperature and low strain rate which makes it a useful tool in simulating the ordinary engineering materials at high strain rate and temperature. This alloy has been extensively used as a model material to simulate behavior of engineering materials at high strain rates and temperatures. In this paper, superplastic tin-lead alloy was used at room temperature to simulate the closure of cavities in steels at high temperatures in the hot region under dynamic loading (high strain rate) under the effect of compressive loads using flat platens (open dies). Hollow specimens having different values of bore diameter (Db) to outer diameter (Dout), of the same height and volume were investigated under different values of height reduction percentages ranging from 20% to 80% , and the percentage of cavity closure at each reduction percentage was determined. It was found that the cavity closure percentage increases or decreases at slow rate for reduction percentage in height less than 40% and increases more rapidly for reduction percentages in height above this value. Furthermore, specimens having smaller values of ratio (Db/Dout) resulted in higher percentage of cavity closure than specimens having higher ratios at the same value of reduction in height percentage. Complete cavity closure has occurred in specimens having the ratios of 0.1 and 0.2 at 75% reduction in height.

Effects of Impressed-Current on Sensitivity of Adiabatic Shear of TC6 Titanium Alloy

2013 ◽  
Vol 718-720 ◽  
pp. 107-111
Author(s):  
Kun Sun ◽  
Kai Hua Yue ◽  
Yuan Xu ◽  
Wen Li Xiang ◽  
Wei Zhong
Keyword(s):  
Titanium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Room Temperature ◽  
High Strain ◽  
Adiabatic Shear Band ◽  
Dynamic Compression ◽  
Adiabatic Shear ◽  
Split Hopkinson ◽  
Impressed Current

Dynamic compression test on TC6 titanium alloy samples have been done by using a split Hopkinson bar process and extra circuit under conditions of room temperature and high strain-rate. The effect of impressed-current on sensitivity of adiabatic shear of TC6 titanium alloy has been studied. It is shown that the impressed-current can reduce the sensitivity of adiabatic shear of TC6 titanium alloy under the condition of high strain-rate. Free electron in the samples will do direct move and take heat away from high localized area to decrease the effect of the heat. The result will help to delay formation of the adiabatic shear band. So, that is reducing the sensitivity of adiabatic shear of TC6 titanium alloy.

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