Structural and Diffusional Effects of Hydrogen in TiNi

نویسندگان

  • A. Pelton
  • C. Trépanier
  • X.-Y. Gong
  • A. Wick
  • K. C. Chen
  • Alan R. Pelton
  • Christine Trépanier
  • Xiao-Yan Gong
  • Andreas Wick
  • Katherine C. Chen
چکیده

Hydrogen can be inadvertently added to Nitinol medical devices through electropolishing, caustic cleaning, or exposure to other acidic or basic solutions. Moderately high hydrogen concentrations can lead to embrittlement characterized by lowered ductility and changes in transformation behavior. The purpose of the present report is to discuss recent results on the effects of hydrogen in annealed TiNi. Samples are charged with hydrogen and analyzed with x-ray diffraction; these data indicate that even relatively small amounts of hydrogen can affect the crystal structure. Additions of up to 1000 wppm hydrogen increase the atomic volume by more than 2%, decrease peak intensity and broaden peak width. These observations are consistent with hydrogen-induced lattice strain. Peak splitting and additional diffraction peaks are observed with the absorption of 6000 wppm hydrogen, which indicates formation of a new phase. It is speculated that the new phase may be based on the B2 structure or may be stress-induced R-phase or martensite. This paper also discusses experiments and analysis on the removal of hydrogen from TiNi wire with 800 wppm through heat treatments at 400-800°C for 30-3000 seconds. Extensive experimental and analytical computations show that the activation energy of hydrogen diffusion under these conditions is approximately 125 kJ/mol.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Gaseous Phase and Electrochemical Hydrogen Storage Properties of Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu) for Nickel Metal Hydride Battery Applications

Structural, gaseous phase hydrogen storage, and electrochemical properties of a series of the Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu) metal hydride alloys were studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed the multi-phase nature of all alloys, which were composed of a stoichiometric TiNi matrix, a hyperstoichiometric TiNi minor phase, and a Ti2Ni seconda...

متن کامل

Structural insights into the effects of charge-reversal substitutions at the surface of horseradish peroxidase

Horseradish peroxidase (HRP), has gained significant interests in biotechnology, especially in biosensor field and diagnostic test kits. Hence, its solvent-exposed lysine residues 174, 232, and 241 have been frequently modified with the aim of improving its stability and catalytic efficiency. In this computational study, we investigated the effects of Lys-to-Glu substitutions on HRP structure t...

متن کامل

Effects of Olibanum Essential Oil on Physicochemical, Structural, Antioxidant and Microbial Characteristics of Gelatin Edible Films

Background and Objectives: Active packaging is an improved form of conventional packaging that can preserve quality of foods and increase durability and safety of food products due to their antimicrobial and antioxidant characteristics.  Materials & Methods: In this study, effects of olibanum essential oil on physicochemical, structural, antimicrobial and antioxidant characteristics of gelatin...

متن کامل

Structural and electronic properties of the martensitic alloys TiNi, TiPd, and TiPt

The electronic and structural properties for TiNi, TiPd, and TiPt are studied using first-principles total energy calculations. For each alloy, the structural parameters for a few structural phases are found from energy and force calculations. In each case, we found that the ground state martensitic phase (B19/B198) is indeed lower in energy than the high temperature B2 phase. In all three allo...

متن کامل

Fatigue behavior of TiNi foams processed by the magnesium space holder technique.

While the wide range of applications of TiNi alloys makes them highly appealing due to their shape memory and superelasticity properties, the production of TiNi in the porous form further enlarges their application fields. Porous TiNi alloys have been studied extensively for biomedical applications since their elastic modulus is similar to that of bone. Accordingly, TiNi foams have been widely ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2003