Showing papers in "Intermetallics in 1998"

TL;DR: In this paper, a new concept of hydrogen absorbing alloy, called Laves phase related BCC solid solution, was proposed, which showed stability of hydrides and reaction kinetics almost identical to intermetallics such as laves phase alloys.

TL;DR: In this paper, a new precision casting process of LEVICAST and induction brazing process of the gamma TiAl and alloy steels were proposed as advanced processing technologies.

TL;DR: In this paper, the Hall-Petch relationship with high constants in fully-lamellar material is explained as a combined function of grain-size and deformation-anisotropy.

TL;DR: In this article, phase equilibrium and thermodynamic data of the binary NiAl system were analyzed using thermodynamic models, where the liquid and fcc (γ) phases were treated as disordered solutions, the intermetallic compounds with appreciable ranges of homogeneity, i.e. γ′-(Ni3Al), B2-(NiAl) and Al3Ni2, were taken to be line compounds.

TL;DR: In this article, microstructural features in the lamellar structures were characterized by metallography, SEM and TEM, and the mechanical properties were determined by tensile tests at temperatures to 1000 °C.

TL;DR: In this article, the tensile and creep properties of orthorhombic alloys in the Ti-Al-Nb system were reviewed with emphasis on tensile properties of ternary alloys.

TL;DR: In this paper, two avenues can be explored for improving high temperature behaviour: modify the diffusive flow behaviour and restrict dislocation motion at dispersed particles. But, while many of its characteristics are well documented, there remains considerable uncertainty about the controlling mechanisms.

TL;DR: In this paper, the properties of some nanostructured Mg2Ni (Mg-33 at%Ni) consisting of nanometer-scale crystallite (intra-grain) and inter-grain regions are discussed.

TL;DR: In this article, the effect of ternary additions, Co and Cr, on martensite transformation temperatures and mechanical properties of offstoichiometric NiTi alloys were investigated.

TL;DR: In this article, phase equilibria in the Nb-Nb-Ti system were experimentally determined and the existence of the phases γ1 (NbTiAl3, tetragonal), T1 (Ti45Al35Nb20, cubic B2) and T2 (T2 45Al45Nb10) at this temperature can be ruled out and the stability of the phase α ∗ (Ti4Al3Nb, hexagonal) is at least questionable.

TL;DR: In this article, the phase equilibria and the crystal structures of the different intermediate phases of the rare earth alloys are discussed and the results obtained in the experimental investigation of the YAl2 and SmAl2 systems are reported.

TL;DR: In this article, the effect of vacancies on mechanical behavior room-temperature compression tests have been performed on polycrystals and single-slip oriented single crystals of Fe-40 at% Al annealed at different temperatures and quenched.

TL;DR: In this paper, the micro-Vickers hardness of MoSi 2 was measured at temperatures in the range from 293 to 1473 K and showed either a plateau region or even a small peak at the temperature range of about 900 to 1200K.

TL;DR: In this paper, the results of recent studies on the deformation and fracture properties of PST crystals, the directional solidification (DS) and microstructural control and the mechanical properties of DS ingots of TiAl-based alloys are summarized.

TL;DR: In this paper, the George-Baker model for the yield strength anomaly of FeAl is reviewed, which is based on hardening by thermal vacancies at intermediate temperatures and dislocation creep at high temperatures.

TL;DR: In this paper, the defect structure of B2-type Fe1 − cAlc alloys (0.44 < c ≤ 0.51) was investigated by in-situ neutron diffraction measurements in the temperature range from room temperature to 1260-1300 K.

TL;DR: In this paper, the transformation behavior of two shape-memory and superelastic L21 ordered single-crystalline Ni-Mn-Ga alloys exhibiting martensitic transformation in the stress-free state at Ms = 287 K Tc (alloy 2), where Tc is Curie temperature, was studied in compression (hydrostatic and/or uniaxial along [110] axis) tests.

TL;DR: In this paper, the fabrication of a powder composed of alumina and titanium trialuminide TiAl 3 from TiO 2 and aluminium powder was reported, and the powders were ball-milled together under vacuum for 100 h in a laboratory scale mill with no reaction evident directly after milling.

TL;DR: In this article, the authors examined the creep strength of Nb3Al-base alloy with two types of different microstructures, equiaxed grains and directionally elongated grains.

TL;DR: Pseudo-binary (Mo0.90Nb0.10)Si2 and (Mo 0.85Nb 0.15) Si2 containing duplex C11b and C40 phases were prepared in a slow solidification process using the floating zone method to obtain basic knowledge regarding control of their microstructure.

TL;DR: In this article, the effects of high temperature exposure on microstructures and tensile properties were examined and it was found that during exposure the α 2 lamellae decomposed to γ phase by a mechanism that involves the formation of thin γ lamella within the original α 2 lambs.

TL;DR: In this article, the phase equilibria among the β (bcc or B2), α (hcp) and γ (L10) phases in Ti-Al-M ternary systems at elevated temperatures have been studied, where the M is β stabilizing element for pure titanium.

TL;DR: In this paper, the ternary phase diagrams of the Ti-Al-X system were proposed, and the tendency of β stabilizer is in the following order: 6 at% Cr = 3 at% Mo = 1 at% W ≒ 10 vol% β phase.

TL;DR: In this article, the coherence stresses expected in various forms of fully coherent TiAl are tabulated and estimates are made of the lamellar thicknesses at which the material becomes semi- or partially coherent and of the residual coherence stress in these materials.

TL;DR: In this article, the effects of boron on the yield strength, lattice parameter, vacancy concentration and anti-site atom concentration of FeAl as a function of aluminum concentration have been compared with data for similar but undoped FeAl.

TL;DR: In this paper, Ta-containing NiAl-base alloys with the Laves phase TaNiAl with C14 structure were modified by alloying with Cr and were studied with respect to constitution, thermal properties, deformation behaviour at ambient and high temperatures.

TL;DR: In this paper, the superplastic behavior of Fe-36.5Al, Fe-1 Ti and Fe-2Ti alloys with large grains has been investigated, and the maximum elongation to fracture of 300% with m value of 0.34 was obtained for Fe36.

TL;DR: In this paper, an experimental investigation on the formation of Al8FeMnSi2 intermetallic particles from AlSiFeMn liquid alloys, in the temperature range from 878 to 973 K, is presented.

TL;DR: In this article, the electronic structure of ternary TiAl-based alloys was calculated by using the discrete variational Xa cluster method, and three parameters, the bond strength, the anisotropy of bond strength and the resistance of the lattice to dislocation motion, were defined to investigate the effects of alloying elements on the ductility of TiAl.

TL;DR: In this paper, specific roles of deformation twinning in the generalized plasticity of polycrystals and the crack-tip microplasticity are discussed in terms of the local strain compatibility by invoking both tension and compression twins.