... 78 (1986) 115-125 115 Cavitation Study in~ Ingot and Powder Metallurgically Processed Superpl... more ... 78 (1986) 115-125 115 Cavitation Study in~ Ingot and Powder Metallurgically Processed Superplastic AI-Li Alloys MC PANDEY, J. WADSWORTH ... occurs by stress-directed vacancy diffusion alone, then according to Raj and Ashby [19] it follows the relationship dr ~6DB( ~) 1 - ...
The authors demonstrate that optical gratings with 600 and 1500 nm periods on a Pd40Ni40P20 bulk ... more The authors demonstrate that optical gratings with 600 and 1500 nm periods on a Pd40Ni40P20 bulk metallic glass (BMG) can be faithfully imprinted in air from Si dies. Results of scanning electron microscopy, atomic force microscopy, and optical diffraction analysis show the fine line feature of ∼150 nm. The gratings have smooth and uniform surface profiles with comparable optical properties as the original Si dies. The BMG gratings can be further used to imprint the second-generation replicas on polymethylmethacrylate. Thereby, BMG is a suitable material not only for imprinting nanostructured parts such as gratings, but also as a good die material for nanoimprints.
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 1996
Enhanced ductilities,i.e., values of tensile ductility exceeding those normally expected in metal... more Enhanced ductilities,i.e., values of tensile ductility exceeding those normally expected in metallic alloys, have been observed at warm temperatures in coarse-grained Al-Mg alloys which exhibit viscous-glide controlled creep. Numerous tests have been conducted in order to quantify this phe-nomenon over wide ranges of temperature and magnesium concentration. The contributions of strain-rate sensitivity and strain hardening have been analyzed in relation to the observed tensile ductilities. It is shown that an analysis based only on flow instability in tension cannot be used to predict failure in a unique manner.
... in a viscous state [5 and 6], reduced sliding friction and improved wear resistance [7], and ... more ... in a viscous state [5 and 6], reduced sliding friction and improved wear resistance [7], and ... tests were initially performed in air which resulted in serious sample oxidation [20]. ... To prepare clean samples for structural analyses, several tensile tests were subsequently conducted in ...
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 1998
Several binary and ternary Al alloys containing from 2.8 to 5.5 wt pct Mg were tested in tension ... more Several binary and ternary Al alloys containing from 2.8 to 5.5 wt pct Mg were tested in tension at elevated temperatures (200°C to 500°C) over a range of strain rates (10−4 to 2.0 s−1). Tensile ductilities of up to 325 pct were obtained in binary Al−Mg alloys with coarse grains deformed in the solute-drag creep regime. Under test conditions in which solute-drag creep controls deformation, Mg in concentrations from 2.8 to 5.5 wt pct neither affects tensile ductility nor influences strain-rate sensitivity or flow stress significantly. Strength is shown to increase with increasing Mg concentration, however, in the power-law-break down regime. The solute-drag creep process, which leads to superplastic-like elongations, is shown to have no observable grain-size dependence in a binary Al−Mg material. Ternary alloying additions of Mn and Zr are shown to decrease the strain-rate sensitivity during solute-drag creep, negatively influencing ductility. An important cause of reduced ductility in the ternary alloys during creep deformation is found to be a transition from necking-controlled failure in the binary alloys to cavitation-controlled failure in the ternary alloys investigated. An increase in ternary element concentration, which can increase the relative volume percentage of proeutectic products, increases cavitation.
... 78 (1986) 115-125 115 Cavitation Study in~ Ingot and Powder Metallurgically Processed Superpl... more ... 78 (1986) 115-125 115 Cavitation Study in~ Ingot and Powder Metallurgically Processed Superplastic AI-Li Alloys MC PANDEY, J. WADSWORTH ... occurs by stress-directed vacancy diffusion alone, then according to Raj and Ashby [19] it follows the relationship dr ~6DB( ~) 1 - ...
The authors demonstrate that optical gratings with 600 and 1500 nm periods on a Pd40Ni40P20 bulk ... more The authors demonstrate that optical gratings with 600 and 1500 nm periods on a Pd40Ni40P20 bulk metallic glass (BMG) can be faithfully imprinted in air from Si dies. Results of scanning electron microscopy, atomic force microscopy, and optical diffraction analysis show the fine line feature of ∼150 nm. The gratings have smooth and uniform surface profiles with comparable optical properties as the original Si dies. The BMG gratings can be further used to imprint the second-generation replicas on polymethylmethacrylate. Thereby, BMG is a suitable material not only for imprinting nanostructured parts such as gratings, but also as a good die material for nanoimprints.
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 1996
Enhanced ductilities,i.e., values of tensile ductility exceeding those normally expected in metal... more Enhanced ductilities,i.e., values of tensile ductility exceeding those normally expected in metallic alloys, have been observed at warm temperatures in coarse-grained Al-Mg alloys which exhibit viscous-glide controlled creep. Numerous tests have been conducted in order to quantify this phe-nomenon over wide ranges of temperature and magnesium concentration. The contributions of strain-rate sensitivity and strain hardening have been analyzed in relation to the observed tensile ductilities. It is shown that an analysis based only on flow instability in tension cannot be used to predict failure in a unique manner.
... in a viscous state [5 and 6], reduced sliding friction and improved wear resistance [7], and ... more ... in a viscous state [5 and 6], reduced sliding friction and improved wear resistance [7], and ... tests were initially performed in air which resulted in serious sample oxidation [20]. ... To prepare clean samples for structural analyses, several tensile tests were subsequently conducted in ...
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 1998
Several binary and ternary Al alloys containing from 2.8 to 5.5 wt pct Mg were tested in tension ... more Several binary and ternary Al alloys containing from 2.8 to 5.5 wt pct Mg were tested in tension at elevated temperatures (200°C to 500°C) over a range of strain rates (10−4 to 2.0 s−1). Tensile ductilities of up to 325 pct were obtained in binary Al−Mg alloys with coarse grains deformed in the solute-drag creep regime. Under test conditions in which solute-drag creep controls deformation, Mg in concentrations from 2.8 to 5.5 wt pct neither affects tensile ductility nor influences strain-rate sensitivity or flow stress significantly. Strength is shown to increase with increasing Mg concentration, however, in the power-law-break down regime. The solute-drag creep process, which leads to superplastic-like elongations, is shown to have no observable grain-size dependence in a binary Al−Mg material. Ternary alloying additions of Mn and Zr are shown to decrease the strain-rate sensitivity during solute-drag creep, negatively influencing ductility. An important cause of reduced ductility in the ternary alloys during creep deformation is found to be a transition from necking-controlled failure in the binary alloys to cavitation-controlled failure in the ternary alloys investigated. An increase in ternary element concentration, which can increase the relative volume percentage of proeutectic products, increases cavitation.
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Papers by Jeffrey Wadsworth