The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

R O Ritchie - One of the best experts on this subject based on the ideXlab platform.

  • effect of product form and heat treatment on the crystallographic texture of austenitic nitinol
    Journal of Materials Science, 2006
    Co-Authors: S W Robertson, Xiaoyan Gong, R O Ritchie
    Abstract:

    The superelastic material Nitinol, a nearly equiatomic alloy of nickel and titanium, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, especially for the fabrication of endovascular stents. The manufacture of these stents, and countless other Nitinol products, originates from various forms of raw material such as tube, sheet or rod. However, depending upon which product form is used, the crystallographic texture in Nitinol can be significantly different, which can lead to marked changes in its mechanical properties. In this paper, we present a study to show the characteristic texture in various Nitinol product forms (tube, sheet, and rod), before and after annealing heat treatments, with specific quantification of the major texture components. We further present predictions of the mechanical response based upon such texture, and provide experimental verification with uniaxial tensile tests. Results show that the form of the starting material has a profound influence on characteristic texture and predicted mechanical response. Furthermore, annealing heat treatments, rather than reducing the texture, are found to increase the strength of this texture.

  • cyclic fatigue of nitinol
    2006
    Co-Authors: S W Robertson, Xiaoyan Gong, J Stankiewicz, R O Ritchie
    Abstract:

    Nitinol's superelasticity, biocompatibilty and magnetic resonance compatibility has led to its increasing popularity for the manufacture of endovascular stents. Despite its growing importance in the Biomedical Industry, especially under conditions involving pulsatile loading, the cyclic fatigue resistance of Nitinol is not well understood. This paper provides a summary of existing data on the fatigue-crack propagation properties of the superelastic alloy and presents preliminary results on crack-growth behavior in samples cut from Nitinol tube used as the starting material for the manufacture of endovascular stents. In addition, a new test sample for measuring the total fatigue life properties is described involving the uniaxial loading of slotted-tubular samples, again machined from Nitinol tube.

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 190–199, 2005

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents.

S W Robertson - One of the best experts on this subject based on the ideXlab platform.

  • effect of product form and heat treatment on the crystallographic texture of austenitic nitinol
    Journal of Materials Science, 2006
    Co-Authors: S W Robertson, Xiaoyan Gong, R O Ritchie
    Abstract:

    The superelastic material Nitinol, a nearly equiatomic alloy of nickel and titanium, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, especially for the fabrication of endovascular stents. The manufacture of these stents, and countless other Nitinol products, originates from various forms of raw material such as tube, sheet or rod. However, depending upon which product form is used, the crystallographic texture in Nitinol can be significantly different, which can lead to marked changes in its mechanical properties. In this paper, we present a study to show the characteristic texture in various Nitinol product forms (tube, sheet, and rod), before and after annealing heat treatments, with specific quantification of the major texture components. We further present predictions of the mechanical response based upon such texture, and provide experimental verification with uniaxial tensile tests. Results show that the form of the starting material has a profound influence on characteristic texture and predicted mechanical response. Furthermore, annealing heat treatments, rather than reducing the texture, are found to increase the strength of this texture.

  • cyclic fatigue of nitinol
    2006
    Co-Authors: S W Robertson, Xiaoyan Gong, J Stankiewicz, R O Ritchie
    Abstract:

    Nitinol's superelasticity, biocompatibilty and magnetic resonance compatibility has led to its increasing popularity for the manufacture of endovascular stents. Despite its growing importance in the Biomedical Industry, especially under conditions involving pulsatile loading, the cyclic fatigue resistance of Nitinol is not well understood. This paper provides a summary of existing data on the fatigue-crack propagation properties of the superelastic alloy and presents preliminary results on crack-growth behavior in samples cut from Nitinol tube used as the starting material for the manufacture of endovascular stents. In addition, a new test sample for measuring the total fatigue life properties is described involving the uniaxial loading of slotted-tubular samples, again machined from Nitinol tube.

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 190–199, 2005

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents.

Mohd Afian Omar - One of the best experts on this subject based on the ideXlab platform.

  • powder injection molding of biocompatible stainless steel biodevices
    Powder Technology, 2016
    Co-Authors: Muhammad Aslam, Puteri Sri Melor Megat Yusoff, Khurram Altaf, Faiz Ahmad, Mohd Afian Omar
    Abstract:

    Although various materials have been exploited throughout history to restore damaged organs, metallic biodevices are preferred in the Biomedical Industry because of their superior ability to withstand high static or cyclic loads. An implant is a medical device manufactured to replace a damaged biological structure. Medical implants are manmade devices and their biocompatibility plays an important role in determine the life of inserted implant. This review presents previous research conducted in the field of corrosion resistance and mechanical properties of bioimplants made of 316L stainless steel (SS) powder using the powder injection molding process. It also establishes a motivational link between the past and present to encourage researchers to conduct constructive studies on the most problematic areas of bioimplants. This article presents a critical review on powder selection, manufacturing techniques, debinding processes, and sintering conditions of 316L SS powders. It also focuses on the influence of powder shape, powder size, powder-to-binder ratios and their effects on densification in terms of corrosion and mechanical properties. In this paper, practical densification approaches are divided into three categories: activation sintering, optimized solid loading, and bimodal mixtures. Additionally, suggestions for the formation of a passive oxide layer on the outer surface of 316L stainless steel implants using powder densification approaches and optimization of sintering parameters are proposed.

Hans-rudolf Wenk - One of the best experts on this subject based on the ideXlab platform.

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 190–199, 2005

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents.

V. Imbeni - One of the best experts on this subject based on the ideXlab platform.

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 190–199, 2005

  • crystallographic texture for tube and plate of the superelastic shape memory alloy nitinol used for endovascular stents
    Journal of Biomedical Materials Research Part A, 2005
    Co-Authors: S W Robertson, V. Imbeni, Hans-rudolf Wenk, R O Ritchie
    Abstract:

    The superelastic/shape-memory material, Nitinol, an approximately equiatomic alloy of Ni and Ti, is rapidly becoming one of the most important metallic implant materials in the Biomedical Industry, in particular for the manufacture of endovascular stents. As such stents are invariably laser-machined from Nitinol tubes or sheets rolled into tubes, it is important to fully understand the physical phenomena that may affect the mechanical behavior of this material. With tubing and plate, one major issue is crystallographic texture, which can play a key role in influencing the mechanical properties of Nitinol. In this article, we present a study on how geometry and heat treatment can affect the texture of Nitinol, with specific quantification of the texture of Nitinol tube used for the production of endovascular stents.