Heterogeneous nucleation in a glass-forming alloy (2008)
Wall, J. J., Liu, C. T., Li, J. J. Z., Liaw, P. K., Choo, H., ...
Nucleation in the undercooled liquid state in the bulk metallic glass-forming composition Zr52.5Cu17.9Ni14.6Al10Ti5 (VIT-105), produced using high purity (PA) and commercial purity (CA) raw materials...
Pseudo-binary phase diagram for Zr-based in situ ß phase composites (2007)
Lee, S. Y., Kim, C. P., Almer, J. D., Lienert, U., Ustundag, E., Johnson, W. L.
The pseudo-binary (quasi-equilibrium) phase diagram for Zr-based bulk metallic glasses with crystalline in situ precipitates (ß phase) has been constructed from high-temperature phase information...
Toward the Holodeck: Integrating Graphics, Sound, Character and Story (2007)
Swartout, W., Hill, R., Gratch, J., Johnson, W. L., Kyriakakis, C., LaBore, C., ...
We describe an initial prototype of a holodeck-like environment that we have created for the Mission Rehearsal Exercise Project. The goal of the project is to create an experience learning system...
Limited Domain Synthesis of Expressive Military Speech for Animated Characters (2007)
Johnson, W. L., Narayanan, Shrikanth, Whitney, Richard, Das, Rajat, LaBore, Catherine
Text-to-speech synthesis can play an important role in interactive education and training applications, as voices for animated agents. Such agents need high-quality voices capable of expressing...
Limited Domain Synthesis of Expressive Military Speech for Animated Characters (2007)
Johnson, W. L., Narayanan, S., Whitney, R., Das, R., Bulut, M., LaBore, C.
Text-to-speech synthesis can play an important role in interactive education and training applications, as voices for animated agents. Such agents need high-quality voices capable of expressing...
Fan, G. J., Freels, M., Choo, H., Liaw, P. K., Li, J. J. Z., Rhim, Won-Kyu, ...
By employing a containerless high-temperature high-vacuum electrostatic levitation technique, the thermophysical properties, including the ratio between the specific heat capacity and the...
On the existence of Einstein oscillators and thermal conductivity in bulk metallic glass (2006)
Zhou, Zhenhua, Uher, Ctirad, Xu, Donghua, Johnson, W. L., Gannon, W., Aronson, M. C.
Low-temperature specific heat and thermal conductivity of bulk metallic glasses are measured to identify the primary vibrational modes associated with their unique structures. An Einstein-type...
Validity of temperature and time equivalence in metallic glasses during shear deformation (2006)
Zink, Mareike, Samwer, K., Johnson, W. L., Mayr, S. G.
Competing internal and external time scales, which are determined by temperature and experimental sampling time—viz., reciprocal frequency—respectively, are essentials for understanding the...
Thermophysical properties of a Cu46Zr42Al7Y5 bulk metallic glass-forming liquid (2006)
Fan, G. J., Li, J. J. Z., Rhim, Won-Kyu, Qiao, D. C., Choo, H., Liaw, P. K., ...
The thermophysical properties, including the specific volume V, the surface tension sigma, and the viscosity eta, of a Cu46Zr42Al7Y5 bulk metallic glass in the molten state were investigated using a...
Zink, Mareike, Samwer, K., Johnson, W. L., Mayr, S. G.
Plastic deformation in metallic glasses well below their glass transition temperatures Tg occurs spatially heterogeneously within highly localized regions, termed shear transformation zones (STZs)....
Room temperature (TR) elastic constants and compressive yield strengths of ~30 metallic glasses reveal an average shear limit gammaC=0.0267±0.0020, where tauY=gammaCG is the maximum resolved shear...
Nucleation is of great concern in many cases—for example, the production of artificial rainfall and the synthesis of advanced amorphous alloys. Although exact solutions have been well known to both...
Surface pinning in an amorphous ZrTiCuNiBe alloy (2005)
Fil, V. D., Fil, D. V., Avramenko, Yu. A., Gaiduk, A. L., Johnson, W. L.
We have measured the amplitude and the phase of an electromagnetic (EM) field radiated from a superconductor (amorphous ZrTiCuNiBe alloy) in the mixed state due to the interaction of the flux lattice...
Mukherjee, S., Schroers, J., Johnson, W. L.
The time-temperature-transformation curves for three zirconium-based bulk amorphous alloys are measured to identify the primary factors influencing their glass-forming ability. The melt viscosity is...
Mukherjee, S., Johnson, W. L., Rhim, W. K.
High-temperature surface tension and viscosities for five bulk metallic glass-forming alloys with widely different glass-forming abilities are measured. The measurements are carried out in a...
Mukherjee, S., Zhou, Z., Schroers, J., Johnson, W. L., Rhim, W. K.
A pronounced effect of overheating is observed on the crystallization behavior for the three zirconium-based bulk metallic glasses: Zr41.2Ti13.8Cu12.5Ni10Be22.5, Zr57Cu15.4Ni12.6Al10Nb5, and...
Surface pinning in amorphous ZrTiCuNiBe alloy (2004)
Fil, V. D., Fil, D. V., Avramenko, Yu. A., Gaiduk, A. L., Johnson, W. L.
We have measured the amplitude and the phase of an electromagnetic (EM) field radiated from superconductor (amorphous ZrTiCuNiBe alloy) in the mixed state due to interaction of the flux lattice with...
Xu, Donghua, Lohwongwatana, Boonrat, Duan, Gang, Johnson, W. L., Garland, Carol
The compositional dependence of a glass-forming ability (GFA) was systematically studied in a binary alloy series Cu100−xZrx (x=34, 36, 38.2, 40 at.%) by the copper mold casting method. Our results...
Shear bands and cracking of metallic glass plates in bending (2003)
Conner, R. D., Johnson, W. L., Paton, N. E., Nix, W. D.
The thickness dependence of yielding and fracture of metallic glass plates subjected to bending is considered in terms of the shear band processes responsible for these properties. We argue that the...
Hays, C. C., Schroers, J., Johnson, W. L., Rathz, T. J., Hyers, R. W., Rogers, J. R., ...
The crystallization kinetics of Zr58.5Nb2.8Cu15.6Ni12.8Al10.3 were studied in an electrostatic levitation (ESL) apparatus. The measured critical cooling rate is 1.75 K/s....
Kim, C. P., Busch, R., Masuhr, A., Choi-Yim, H., Johnson, W. L.
Carbon-fiber-reinforced bulk metallic glass composites are produced by infiltrating liquid Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 into carbon fiber bundles with diameter of the individual fiber of 5 mum....
Pekarskaya, E., Kim, C. P., Johnson, W. L.
In situ straining transmission electron microscopy (TEM) experiments were performed to study the propagation of the shear bands in the Zr56.3Ti13.8Cu6.9Ni5.6Nb5.0Be12.5 bulk metallic glass based...
Schennach, R., Grady, T., Naugle, D. G., McWhinney, H., Hays, C. C., Johnson, W. L., ...
Bulk amorphous alloys are a new class of materials with a variety of characteristics that make them useful for applications in aqueous environments. While some bulk amorphous metals show increased...
Crystallization of amorphous Cu47-Ti34-Zr11-Ni8 (2001)
Glade, S. C., Löffler, J. F., Bossuyt, S., Johnson, W. L., Miller, M. K.
The results of a study on the crystallization of amorphous Cu47-Ti34-Zr11-Ni8 with the use of differential scanning calorimetry, transmission electron microscopy (TEM), x-ray diffraction, field ion...
Bezuglyi, E. V., Gaiduk, A. L., Fil, V. D., Zherlitsyn, S., Johnson, W. L., Bruls, G., ...
The crossing of the temperature dependences of sound velocity in the normal and the superconducting state of metallic glasses indicates renormalization of the intensity of sound interaction with...
Viscous flow of the Cu47-Ti34-Zr11-Ni8 glass forming alloy (2000)
The viscosity of the Cu47-Ti34-Zr11-Ni8 glass forming alloy was determined by beam bending experiments and by a noncontact oscillating drop technique. These viscosity data can be described with the...
Glade, S. C., Busch, R., Lee, D. S., Johnson, W. L., Wunderlich, R. K., Fecht, H. J.
The differences in the thermodynamic functions between the liquid and the crystalline states of three bulk metallic glass forming alloys, Cu47Ti34Zr11Ni8, Zr52.5Cu17.9Ni14.6Al10Ti5, and...
Hays, C. C., Kim, C. P., Johnson, W. L.
Results are presented for a ductile metal reinforced bulk metallic glass matrix composite based on glass forming compositions in the Zr-Ti-Cu-Ni-Be system. Primary dendrite growth and solute...
Bezuglyi, E. V., Gaiduk, A. L., Fil, V. D., Zherlitsyn, S. V., Johnson, W. L., Bruls, G., ...
The crossing of temperature dependencies of sound velocity in the normal and the superconducting state of metallic glasses indicates renormalization of the intensity of sound interaction with...
Sound attenuation in the superconducting amorphous alloy ZrTiCuNiBe (1999)
Bezuglyi, E. V., Gaiduk, A. L., Fil, V. D., Johnson, W. L., Bruls, G., Lüthi, B., ...
The superconducting energy gap and the parameter eta determining the intensity of electron scattering at two-level systems in amorphous ZrTiCuNiBe are determined from the results of measurements of...
Sound attenuation in the superconducting amorphous alloy ZrTiCuNiBe (1999)
Bezuglyi, E. V., Gaiduk, A. L., Fil, V. D., Johnson, W. L., Bruls, G., Luethi, B., ...
The superconducting energy gap and the parameter of the intensity of electron scattering at two-level systems in amorphous ZrTiCuNiBe are determined from the results of measurements of sound...
Hays, C. C., Kim, C. P., Johnson, W. L.
Results of calorimetric, differential thermal analysis, and structural measurements are presented for a series of bulk metallic glass forming compositions in the Zr-Ti-Cu-Ni-Be alloy system. The...
Schroers, J., Busch, R., Masuhr, A., Johnson, W. L.
Isothermal crystallization studies are performed on Zr41Ti14Cu12Ni10Be23 melts between the liquidus and the glass transition temperature. The resulting time–temperature-transformation diagram is in...
Liu, W., Johnson, W. L., Schneider, S., Geyer, U., Thiyagarajan, P.
We report on a small-angle x-ray-scattering (SAXS) and differential scanning calorimetry study of phase separation and crystallization in rapidly quenched amorphous Mg62Cu25Y10Li3 alloy samples....
Masuhr, A., Waniuk, T. A., Busch, R., Johnson, W. L.
The shear viscosity of liquid Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 has been measured. At the liquidus temperature we find an extremely high viscosity of 2.5 Pa s, favoring glass formation. At deep...
Samwer, K., Busch, R., Johnson, W. L.
The change of the compressibility at the glass transition Tg is evaluated from pressure experiments in the liquid and the glassy state of the ZrTiCuNiBe bulk metallic glass forming system. Via the...
Melt infiltration casting of bulk metallic-glass matrix composites (1998)
Dandliker, R. B., Conner, R. D., Johnson, W. L.
The authors describe a technique for melt infiltration casting of composites with a metallic-glass matrix. We made rods 5 cm in length and 7 mm in diameter. The samples were reinforced by continuous...
Choi-Yim, H., Busch, R., Johnson, W. L.
Composites of the Cu47Ti34Zr11Ni8 bulk metallic glass, reinforced with up to 30 vol % SiC particles are synthesized and characterized. Results based on x-ray diffraction, optical microscopy, scanning...
Viscosity and enthalpy relaxation from the amorphous state into the supercooled liquid state was investigated in the bulk metallic glass forming Zr46.75Ti8.25Cu7.5Ni10Be27.5 alloy below the...
Thermodynamics and kinetics of the Mg65Cu25Y10 bulk metallic glass forming liquid (1998)
Busch, R., Liu, W., Johnson, W. L.
The thermodynamics and kinetics of the bulk metallic glass forming Mg65Cu25Y10 liquid were investigated using differential scanning calorimetry and three-point beam bending. The experiments lead to...
Bezuglyi, E. V., Gaiduk, A. L., Fil, V. D., Johnson, W. L., Bruls, G., Luethi, B., ...
The crossing of temperature dependences of the sound velocity in normal and superconducting state of metallic glasses points out unambiguously the renormalization of the intensity of sound...
Bulk metallic glass matrix composites (1997)
Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to...
Low-temperature acoustic characteristics of the amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be22.5 (1997)
Gaiduk, A. L., Bezuglyi, E. V., Fil, V. D., Johnson, W. L.
The temperature dependences of the sound velocity v and attenuation alpha of high-frequency (50–160 MHz) sound in the bulk amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be22.5 are studied at helium...
Fracture toughness and fatigue-crack propagation in a Zr–Ti–Ni–Cu–Be bulk metallic glass (1997)
Gilbert, C. J., Ritchie, R. O., Johnson, W. L.
The recent development of metallic alloy systems which can be processed with an amorphous structure over large dimensions, specifically to form metallic glasses at low cooling rates (similar to 10...
Specific Volumes of the Alloy in the Liquid, and Crystalline States (1997)
K. Ohsaka, A. And, W. L. Johnson
The specific volumes of the alloy as a function of temperature, are determined by employing an digitizing technique and numerical calculation methods applied the electrostatically levitated spherical...
Collected Papers of the Soar/IFOR Project. Spring 1995. (1997)
Johnson, W. L., Jones, Randolph M., Koss, Frank V., Laird, John E., Lehman, Jill F.
Since the summer of 1992, the Soar/IFR research group has been building intelligent automated agents for tactical air simulation. The Soar/IFOR research project exists at three sites, the University...
Ohsaka, K., Chung, S. K., Rhim, W. K., Peker, A., Scruggs, D., Johnson, W. L.
The specific volumes of the Zr41.2Ti13.8CU12.5Ni10.0Be2.25 alloy as a function of temperature, T, are determined by employing an image digitizing technique and numerical calculation methods applied...
Noncontact modulation calorimetry of metallic liquids in low Earth orbit (1997)
Wunderlich, R. K., Lee, D. S., Johnson, W. L.
Noncontact modulation calorimetry using electromagnetic heating and radiative heat loss under ultrahigh-vacuum conditions has been applied to levitated solid, liquid, and metastable liquid samples....
Oxidation and crystallization of an amorphous Zr60Al15Ni25 alloy (1996)
Sun, X., Schneider, S., Geyer, U., Johnson, W. L., Nicolet, M-A.
The amorphous ternary metallic alloy Zr60Al15Ni25 was oxidized in dry oxygen in the temperature range 310 ±C to 410 ±C. Rutherford backscattering (RBS) and cross-sectional transmission electron...
Geyer, U., Johnson, W. L., Schneider, S., Qiu, Y., Tombrello, T. A.
Be diffusivity data in the bulk metallic glass forming alloy Zr46.7Ti8.3Cu7.5Ni10Be27.5 are reported for temperatures between 530 and 710 K, extending 85 K into the supercooled liquid state of the...
Precipitation of bcc nanocrystals in bulk Mg–Cu–Y amorphous alloys (1996)
Coexistent amorphous and nanoscale bcc-Mg7Li3 phases were found in slowly quenched alloys of the Mg65–xLixCu25Y10 system containing 3 to 15 at.% Li. The crystallization behavior of these alloys has...
Surface microstructure of Zr41.25Ti13.75Cu12.5Ni10.0Be22.5, a bulk metallic glass (1996)
LaMadrid, M. A., O'Connor, S. D., Peker, A., Johnson, W. L., Baldeschwieler, J. D.
The surface of Zr41.25Ti13.75Cu12.5Ni10.0Be22.5, a bulk metallic glass prepared by RF induction melting, has been imaged using atomic force microscopy. The untreated surfaces were very smooth;...
Supercooled melting in multicomponent Zr–Al–Cu–Ni diffusion couples (1996)
Busch, R., Bakke, E., Johnson, W. L.
Diffusion couples combining a hcp Zr90Al10 supersaturated solid solution with a fcc Cu64Ni36 solid solution were annealed at 410 °C for different times. The reaction at the interface was...
Kim, Y. J., Busch, R., Johnson, W. L., Rulison, A. J., Rhim, W. K.
High temperature high vacuum electrostatic levitation was used to determine the complete time–temperature–transformation (TTT) diagram of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass...
The dynamic compressive behavior of beryllium bearing bulk metallic glasses (1996)
Bruck, H. A., Rosakis, A. J., Johnson, W. L.
In 1993, a new beryllium bearing bulk metallic glass with the nominal composition of Zr41.25Ti13.75Cu12.5Ni10Be22.5 was discovered at Caltech. This metallic glass can be cast as cylindrical rods as...
Schneider, S., Thiyagarajan, P., Johnson, W. L.
Primary crystallization and decomposition in the bulk amorphous alloy Ar41.2Ti13.8Cu12.5Ni10Be22.5 have been studied by small angle neutron scattering (SANS), transmission electron microscopy (TEM),...
Formation of Ti–Zr–Cu–Ni bulk metallic glasses (1995)
Formation of bulk metallic glass in quaternary Ti–Zr–Cu–Ni alloys by relatively slow cooling from the melt is reported. Thick strips of metallic glass were obtained by the method of metal mold...
Bakke, E., Busch, R., Johnson, W. L.
The viscosity of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 bulk metallic glass forming alloy in the supercooled liquid was measured using parallel plate rheometry. The measurements were carried out with...
Geyer, U., Schneider, S., Johnson, W. L., Qiu, Y., Tombrello, T. A.
The self-diffusivity of Be in the bulk metallic amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be22.5 is investigated. Below the glass transition temperature the data suggest a single atomic jump diffusion...
Decomposition and primary crystallization in undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 melts (1995)
Busch, R., Schneider, S., Peker, A., Johnson, W. L.
Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glasses were prepared by cooling the melt with a rate of about 10 K/s and investigated with respect to their chemical and structural homogeneity by atom...
Busch, R., Kim, Y. J., Johnson, W. L., Rulison, A. J., Rhim, W. K., Isheim, D.
High-temperature high-vacuum electrostatic levitation (HTHVESL) and differential scanning calorimetry (DSC) were combined to determine the hemispherical total emissivity epsilon T, and the specific...
Busch, R., Kim, Y. J., Johnson, W. L.
Differential scanning calorimetry (DSC) was used to determine the thermodynamic functions of the undercooled liquid and the amorphous phase with respect to the crystalline state of the...
Kim, Y. J., Busch, R., Johnson, W. L., Rulison, A. J., Rhim, W. K.
Various sample sizes of Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 with masses up to 80 mg were undercooled below Tg (the glass transition temperature) while electrostatically levitated. The final solidification...
A highly processable metallic glass: Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 (1993)
We report on the properties of one example of a new family of metallic alloys which exhibit excellent glass forming ability. The critical cooling rate to retain the glassy phase is of the order of 10...
Search for instability-induced amorphization in deuterated ErFe2 (1993)
Li, J., Yelon, W. B., Johnson, W. L.
Experimental evidence–in the form of a specific-heat anomaly–for instability-induced amorphization of ErFe2 by hydrogenation was recently reported by Fecht, Fu, and Johnson [Phys. Rev. Lett. 64,...
Gibbs free-energy difference between the glass and crystalline phases of a Ni-Zr alloy (1993)
Ohsaka, K., Trinh, E. R., Holzer, J. C., Johnson, W. L.
The heats of eutectic melting and devitrification, and the specific heats of the crystalline, glass, and liquid phases have been measured for a Ni24Zr76 alloy. The data are used to calculate the...
Mechanically driven alloying and grain size changes in nanocrystalline Fe-Cu powders (1993)
Eckert, J., Holzer, J. C., Johnson, W. L.
Highly supersaturated nanocrystalline FexCu100-x alloys (10 less-than-or-equal-to x less-than-or-equal-to 95) have been prepared by mechanical alloying of elemental crystalline powders. The...
Eckert, J., Holzer, J. C., Johnson, W. L.
X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry were used to study the thermal stability of highly supersaturated nanocrystalline FexCu100−x alloys (10