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William L Johnson - One of the best experts on this subject based on the ideXlab platform.

  • compression compression fatigue of pd43ni10cu27p20 metallic glass foam
    Journal of Applied Physics, 2010
    Co-Authors: Gongyao Wang, Joseph P. Schramm, P K Liaw, Marios D Demetriou, William L Johnson
    Abstract:

    Compression-compression fatigue testing of metallic-glass foam is performed. A stress-life curve is constructed, which reveals an Endurance Limit at a fatigue ratio of about 0.1. The origin of fatigue resistance of this foam is identified to be the tendency of intracellular struts to undergo elastic and reversible buckling, while the fatigue process is understood to advance by anelastic strut buckling leading to localized plasticity (shear banding) and ultimate strut fracture. Curves of peak and valley strain versus number of cycles coupled with plots of hysteresis loops and estimates of energy dissipation at various loading cycles confirm the four stages of foam-fatigue.

  • Compression-compression fatigue of Pd_(43)Ni_(10)Cu_(27)P_(20) metallic glass foam
    2010
    Co-Authors: Gongyao Wang, Joseph P. Schramm, P K Liaw, Marios D Demetriou, William L Johnson
    Abstract:

    Compression-compression fatigue testing of metallic-glass foam is performed. A stress-life curve is constructed, which reveals an Endurance Limit at a fatigue ratio of about 0.1. The origin of fatigue resistance of this foam is identified to be the tendency of intracellular struts to undergo elastic and reversible buckling, while the fatigue process is understood to advance by anelastic strut buckling leading to localized plasticity (shear banding) and ultimate strut fracture. Curves of peak and valley strain versus number of cycles coupled with plots of hysteresis loops and estimates of energy dissipation at various loading cycles confirm the four stages of foam-fatigue.

  • fracture and fatigue behavior of a zr ti nb ductile phase reinforced bulk metallic glass matrix composite
    Scripta Materialia, 2003
    Co-Authors: Katharine M Flores, William L Johnson, Reinhold H Dauskardt
    Abstract:

    Abstract The fracture and fatigue behavior of a Zr-based metallic glass composite are presented. The fracture resistance and fatigue Endurance Limit was significantly higher than that of the matrix material. Results are rationalized in terms of the effects of the second phase on shear band formation and distribution.

L D Zardiackas - One of the best experts on this subject based on the ideXlab platform.

  • structure metallurgy and mechanical properties of a porous tantalum foam
    Journal of Biomedical Materials Research, 2001
    Co-Authors: L D Zardiackas, Douglas E Parsell, Lance D Dillon, Darrell W Mitchell, Laura A Nunnery, R A Poggie
    Abstract:

    This study evaluated a porous tantalum biomaterial (Hedrocel™) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240–393, compressive strength was 60 ± 18 MPa, tensile strength was 63 ± 6 MPa, and bending strength was 110 ± 14 MPa. The compressive fatigue Endurance Limit was 23 MPa at 5 × 106 cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45° to the axis of the applied load. The cantilever bending fatigue Endurance Limit was 35 MPa at 5 × 106 cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 180–187, 2001

  • structure metallurgy and mechanical properties of a porous tantalum foam
    Journal of Biomedical Materials Research, 2001
    Co-Authors: L D Zardiackas, Douglas E Parsell, Lance D Dillon, Darrell W Mitchell, Laura A Nunnery, R A Poggie
    Abstract:

    This study evaluated a porous tantalum biomaterial (Hedrocel) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240-393, compressive strength was 60 +/- 18 MPa, tensile strength was 63 +/- 6 MPa, and bending strength was 110 +/- 14 MPa. The compressive fatigue Endurance Limit was 23 MPa at 5 x 10(6) cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45 degrees to the axis of the applied load. The cantilever bending fatigue Endurance Limit was 35 MPa at 5 x 10(6) cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation.

Reinhold H Dauskardt - One of the best experts on this subject based on the ideXlab platform.

R A Poggie - One of the best experts on this subject based on the ideXlab platform.

  • structure metallurgy and mechanical properties of a porous tantalum foam
    Journal of Biomedical Materials Research, 2001
    Co-Authors: L D Zardiackas, Douglas E Parsell, Lance D Dillon, Darrell W Mitchell, Laura A Nunnery, R A Poggie
    Abstract:

    This study evaluated a porous tantalum biomaterial (Hedrocel™) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240–393, compressive strength was 60 ± 18 MPa, tensile strength was 63 ± 6 MPa, and bending strength was 110 ± 14 MPa. The compressive fatigue Endurance Limit was 23 MPa at 5 × 106 cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45° to the axis of the applied load. The cantilever bending fatigue Endurance Limit was 35 MPa at 5 × 106 cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 180–187, 2001

  • structure metallurgy and mechanical properties of a porous tantalum foam
    Journal of Biomedical Materials Research, 2001
    Co-Authors: L D Zardiackas, Douglas E Parsell, Lance D Dillon, Darrell W Mitchell, Laura A Nunnery, R A Poggie
    Abstract:

    This study evaluated a porous tantalum biomaterial (Hedrocel) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240-393, compressive strength was 60 +/- 18 MPa, tensile strength was 63 +/- 6 MPa, and bending strength was 110 +/- 14 MPa. The compressive fatigue Endurance Limit was 23 MPa at 5 x 10(6) cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45 degrees to the axis of the applied load. The cantilever bending fatigue Endurance Limit was 35 MPa at 5 x 10(6) cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation.

P K Liaw - One of the best experts on this subject based on the ideXlab platform.

  • fatigue behavior of al0 5cocrcufeni high entropy alloys
    Acta Materialia, 2012
    Co-Authors: Michael A Hemphill, Gongyao Wang, Chungmin Tsai, A Chuang, Tao Yuan, P K Liaw
    Abstract:

    Abstract Research was performed on an Al 0.5 CoCrCuFeNi high entropy alloy (HEA) in an attempt to study the fatigue behavior. The present fatigue investigation shows encouraging fatigue resistance characteristics due to the prolonged fatigue lives of various samples at relatively high stresses. The current results indicate that the fatigue behavior of HEAs compares favorably with many conventional alloys, such as steels, titanium alloys, and advanced bulk metallic glasses with a fatigue Endurance Limit of between 540 and 945 MPa and a fatigue Endurance Limit to ultimate tensile strength ratio of between 0.402 and 0.703. Some unpredictability in the fatigue life of the samples was observed as scattering in the stress vs. lifetime plot. Weibull models were applied to predict the fatigue data and to characterize the variability seen in the HEAs. A Weibull mixture predictive model was used to separate the data into two, strong and weak, groups. This model predicts that at stresses above 858 MPa the median time to failure of specimens in the strong group will be greater than 10 7  cycles. It was shown that microstructural defects, such as aluminum oxide inclusions and microcracks, may have a significant effect on the fatigue behavior of HEAs. It is believed that a reduction in the number of these defects may result in a fatigue behavior which exceeds that of conventional alloys.

  • compression compression fatigue of pd43ni10cu27p20 metallic glass foam
    Journal of Applied Physics, 2010
    Co-Authors: Gongyao Wang, Joseph P. Schramm, P K Liaw, Marios D Demetriou, William L Johnson
    Abstract:

    Compression-compression fatigue testing of metallic-glass foam is performed. A stress-life curve is constructed, which reveals an Endurance Limit at a fatigue ratio of about 0.1. The origin of fatigue resistance of this foam is identified to be the tendency of intracellular struts to undergo elastic and reversible buckling, while the fatigue process is understood to advance by anelastic strut buckling leading to localized plasticity (shear banding) and ultimate strut fracture. Curves of peak and valley strain versus number of cycles coupled with plots of hysteresis loops and estimates of energy dissipation at various loading cycles confirm the four stages of foam-fatigue.

  • Compression-compression fatigue of Pd_(43)Ni_(10)Cu_(27)P_(20) metallic glass foam
    2010
    Co-Authors: Gongyao Wang, Joseph P. Schramm, P K Liaw, Marios D Demetriou, William L Johnson
    Abstract:

    Compression-compression fatigue testing of metallic-glass foam is performed. A stress-life curve is constructed, which reveals an Endurance Limit at a fatigue ratio of about 0.1. The origin of fatigue resistance of this foam is identified to be the tendency of intracellular struts to undergo elastic and reversible buckling, while the fatigue process is understood to advance by anelastic strut buckling leading to localized plasticity (shear banding) and ultimate strut fracture. Curves of peak and valley strain versus number of cycles coupled with plots of hysteresis loops and estimates of energy dissipation at various loading cycles confirm the four stages of foam-fatigue.