Thickness-Dependent Permanent Magnet Properties of Zr $$_{2}$$ Co $$_{11}$$ Thin Films Grown on Si with Pt Underlayer

Metallurgical and Materials Transactions A - Zr-Co is one of the essential magnetic materials due to its interesting magnetic and structural properties. In this work, we studied the magnetic and...     

Segregation enthalpies of phosphorus,carbon and silicon at {013} and {012} symmetrical tilt grain boundaries in an Fe-3.5 at.% Si alloy

The temperature dependence of the chemical composition of {013} and {012} symmetrical tilt grain boundaries in Σ = 5 36.9°[100] and 53.1°[100] bicrystals, respectively, of an Fe-3.5 at.% Si alloy containing traces of P and C was determined by quantitative Auger electron spectroscopy. The enrichment of P and C and the depletion of Si observed at both interfaces in the whole temperature range between 773 and 1173 K can be described by weak attractive FeC and SiC and a weak repulsive PC interactions together with a strong repulsive SiP interaction. The marked differences in the segregation behavior of both grain boundaries are represented by the determined segregation enthalpies of P, Si and C which are −13.4, −9 and −40 kJ/mol, respectively, for the {013} grain boundary and −11.0, −4 and −35 kJ/mol, respectively, for the {012} grain boundary.     

Energy of the Pb{111}‖Al{111} interface

The energy of the Pb{111}‖Al{111} interface has been determined by a solid-state wetting technique. Pb crystallites, 18 μm or less in size, were equilibrated on a monocrystalline Al{111} substrate at 590 K under ultrahigh vacuum conditions. Auger electron spectroscopy of the equilibrated sample showed that about 1.8 monolayers of Pb are adsorbed on the surface of the Al substrate, but that no Al is adsorbed on the Pb surface. The contact angle of Pb crystallites with the orientation relationship Pb{111}∥Al{111} was measured to be 27.3±0.8 deg. After correction of the Al surface energy for Pb adsorption, by means of the Gibbs adsorption isotherm, the Young equation was used to obtain an interfacial energy of 217±35 mJ m⁻².     

{011} Twinning in Fe-Ni-C martensites

The substructures of two Fe-Ni-C alloys that form platelike martensite have been studied by transmission electron microscopy (TEM). Planar features with a {011 } habit are observed, in addition to the usual {112 } transformation twins and arrays of screw dislocations. The results of diffraction-contrast experiments are consistent with these {011 } defects being fine twins within which the carbon atoms occupy a different octahedral interstitial sublattice from the surrounding matrix. In any given martensitic plate, this twinning appears to occur preferentially on the {011 } plane containing the same {111 } direction as the operative {112 } transformation-twinning variant. The possibility that {011 } twinning occurs during the martensitic transformation and/or when virgin martensite is heated from subambient temperatures is discussed in relation to crystallographic observables such as the martensitic habit plane and axial ratios. The tetragonal symmetry of martensite dictates that the absolute value of the underlined index be fixed when obtaining equivalent crystallographic variants. Small contractions along the αa- andb-axes accompany the expansion along thec-axis. formerly with the Massachusetts Institute of Technology, formerly with the Massachusetts Institute of Technology