Calorimetrically measured enthalpies for the reaction of H[sub 2](D[sub 2]) (g) with Ti and Ti-Ni alloys at 323 K

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Metallurgical Transactions, B (Process Metallurgy); (United States)

DOI:https://doi.org/10.1007/BF02663147· OSTI ID:6079531

Luo, W ^[1]; Clewley, J D; Flanagan, T B ^[2]

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1. Brookhaven National Lab., Upton, NY (United States)
2. Univ. of Vermont, Burlington, VT (United States)

Reaction enthalpies have been measured calorimetrically at 323 K for the reaction 1/2H[sub 2] (g) + Ti ([alpha], hcp) [yields] TiH[sup 1.5] and for the partial molar solution of H[sub 2] in the [delta] phase. The magnitude of the enthalpy decreases from 68 at H/Ti = 0 to 65 kJ/mol H at H/Ti = 1.5. The enthalpy continues to slowly fall in magnitude with the increase of H content, and then, for (H/Ti) > 1.9, it falls more precipitously. [Delta]H[sub f][sup 0](TiH[sup 1.5]) = [minus]98.4 kJ and [Delta]H[sub f][sup 0](TiH[sub 2]) = [minus]130.3 kJ evaluated at 323 K. No differences in enthalpies were found between H and D. The results are discussed in terms of the existing solvus data for this system, which are important for the quantitative understanding of hydride-induced fracture. Enthalpies of reaction with H[sub 2] have been determined for several Ti-Ni alloys which lie in the (Ti([alpha]) + Ti[sub 2]Ni) two-phase field. The reaction with H[sub 2] initially occurs with the Ti phase and then with the Ti[sub 2]Ni phase. The enthalpies are similar for the Ti phase as for pure Ti, indicating that this phase is relatively pure Ti. Reaction with the Ti[sub 2]Ni phase shows a plateau region with an enthalpy of reaction with 1/2H[sub 2] of about [minus]30 kJ/mol H.

• OSTI ID: 6079531
• Journal Information: Metallurgical Transactions, B (Process Metallurgy); (United States), Journal Name: Metallurgical Transactions, B (Process Metallurgy); (United States) Vol. 24B:5; ISSN MTTBCR; ISSN 0360-2141
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CALORIMETRY
DEUTERIUM
ELEMENTS
EMBRITTLEMENT
ENTHALPY
FRACTURE PROPERTIES
HYDROGEN
HYDROGEN EMBRITTLEMENT
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MECHANICAL PROPERTIES
METALS
NICKEL ALLOYS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PHYSICAL PROPERTIES
REACTION HEAT
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TITANIUM
TITANIUM ALLOYS
TRANSITION ELEMENTS