Malleable hypoeutectic Zr–Ni–Cu–Al bulk glassy alloys with tensile plastic elongation at room temperature

2009 ◽  
Vol 89 (5) ◽  
pp. 322-334 ◽  
Author(s):  
Y. Yokoyama ◽  
K. Fujita ◽  
A.R. Yavari ◽  
A. Inoue
Keyword(s):  
Room Temperature ◽  
Glassy Alloys ◽  
Plastic Elongation

scholarly journals Formation and mechanical properties of Cu–Hf–Ti bulk glassy alloys [Article Retracted]

2001 ◽  
Vol 16 (10) ◽  
pp. 2836-2844 ◽  
Author(s):  
Akihisa Inoue ◽  
Wei Zhang ◽  
Tao Zhang ◽  
Kei Kurosaka
Keyword(s):  
Fracture Strength ◽  
Glassy Alloy ◽  
Supercooled Liquid Region ◽  
Maximum Diameter ◽  
Tensile Fracture ◽  
Liquid Region ◽  
High Fracture ◽  
Glassy Alloys ◽  
Plastic Elongation ◽  
Bulk Glassy Alloy

High-strength Cu-based bulk glassy alloys were formed in the Cu–Hf–Ti system by the copper mold casting and melt clamp forging methods. The maximum diameter is 4 mm for the Cu60Hf25Ti15 alloy. The substitution of Hf in the Cu60Hf40 alloy by Ti causes an increase in the glass-forming ability (GFA). As the Ti content increases, the glass transition temperature (Tg) decreases, while the crystallization temperature (Tx) shows a maximum at 5% Ti and then decreases, resulting in a maximum supercooled liquid region ΔTx (= Tx − Tg) of 78 K at 5% Ti. The liquidus temperature (T1) has a minimum of 1172 K around 20% Ti, and hence, a maximum Tg//T1 of 0.62 is obtained at 20% Ti. The high GFA was obtained at the compositions with high Tg/T1. The bulk glassy alloy exhibits tensile fracture strength of 2130 MPa, compressive fracture strength of 2160 MPa, and compressive plastic elongation of 0.8 to 1.6%. The new Cu-based bulk glassy alloys with high Tg/T1 above 0.60, high fracture strength above 2100 MPa, and distinct plastic elongation are encouraging for future development as a new type of bulk glassy alloy that can be used for structural materials.

Investigation of Electrical Properties in Chalcogenide Thin Film According to Wave Length

2007 ◽  
Vol 31 ◽  
pp. 135-137
Author(s):  
H. Choi ◽  
H.K. Kim ◽  
Y.W. Koo ◽  
K.H. Nam ◽  
S.M. Koo ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Wave Length ◽  
Potential Candidate ◽  
Melt Quenching ◽  
Programmable Metallization Cell ◽  
Glassy Alloys ◽  
Electrochemical Control ◽  
Evaporation Technique ◽  
Chalcogenide Thin Film

Programmable metallization cell (PMC) memory is based on the electrochemical control of nanoscale quantities of metal in thin films of solid electrolyte. We investigate the nature of thin films formed by the photo-dissolution of Ag into Ge-Se-Te glasses for use in programmable metallization cell devices. Glassy alloys of a-Ge25Se75-xTex(x = 0, 25) are prepared by well known melt-quenching technique. Thin films of a-Ge25Se75-xTex(x = 0, 25) glassy alloys are evaporated by vacuum evaporation technique at ~10-6 torr on glass substrate at room temperature. Optical properties in this study concerns photo-diffusion of Ag on Ag-doped Ge-Se-Te electrolytes. With these promising properties, the composition a-Ge25Se75-xTex(x = 0, 25) is recommended as a potential candidate for PMC-RAM.

ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF A-Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) THIN FILMS

2013 ◽  
Vol 22 ◽  
pp. 439-451
Author(s):  
AMBIKA SHARMA ◽  
KUMARI ANSHU ◽  
PREETI YADAV
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Life Time ◽  
Defect States ◽  
Temperature Dependent ◽  
Photoelectrical Properties ◽  
Glassy Alloys ◽  
Localized State ◽  
Evaporation Technique ◽  
Density Of Defect States

Bulk samples of Te-rich Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) glassy alloys are prepared by melt quenching technique. The thin films of the bulk samples are deposited by using vacuum evaporation technique for their electrical and photoelectrical measurements. Keithley 6487 picoammeter has been used to study the electrical and photoelectrical characteristics of Ge20Te80-XBix thin films kept in vacuum. Temperature dependent dark and photoconductivity is studied in the temperature range 300-360 K and voltage V = 80V. Photoconductivity with intensity at room temperature follows a power law where power γ lies near to 0.5, suggesting that the recombination is bimolecular in nature. The density of defect states and photosensitivity are found to follow an opposite trend with each other. The differential life time is determined from the rise and decay of photocurrent w.r.t. time. The dispersion parameter and localized state distribution parameter are estimated from decay curves and reported for the studied composition.

Internal Friction and Mechanical Strength of Hydrogenated Ti-Rich Multicomponent Glassy Alloys

2006 ◽  
Vol 319 ◽  
pp. 139-144 ◽  
Author(s):  
Masuyuki Hasegawa ◽  
M. Takeuchi ◽  
D. Nagata ◽  
T. Wada ◽  
Hidemi Kato ◽  
...  
Keyword(s):  
Activation Energy ◽  
Tensile Strength ◽  
Internal Friction ◽  
Mechanical Strength ◽  
Room Temperature ◽  
Peak Temperature ◽  
Internal Friction Peak ◽  
Exponential Factor ◽  
Similar Composition ◽  
Glassy Alloys

The hydrogen-induced internal friction and mechanical strength of the Ti-rich Ti34Zr11Cu47Ni8 and (Ti34Zr11Cu47Ni8)98Si2 hydrogenated glassy alloys have been investigated. It is found that the tensile strength is more than 0.8 GPa at room temperature when the hydrogen content is below about 20 at% for both alloys. The frequency dependence of peak temperature of the hydrogen-induced internal friction of (Ti34Zr11Cu47Ni8)98Si2-17.3 at%H hydrogenated glassy alloys has been clarified. Activation energy and pre-exponential factor are estimated to be 0.35 eV and 1.3x10-12, respectively. Compared with these values with those of Zr40Cu49Al10Si1 hydrogenated glassy alloys which show an internal friction peak around 300 K at about 300 Hz, it is found that the activation energy is much smaller than that of the latter although the pre-exponential factor is almost the same. Considering their similar composition and different component (Al), it is suggested that the component Al of the latter glassy alloys is effective for the higher activation energy which results in the increase of the peak temperature.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

Sign in / Sign up

Export Citation Format

Share Document