Magnetic properties of nano-crystalline Fe-Cr alloys prepared bymechanical alloying

Fe-Cr powdered alloys synthesized via mechanical attrition have been examined by magnetization and 57Fe Mossbauer spectroscopy. Mossbauer studies reveal that Fe1-xCrx becomes paramagnetic for x⩾0.46 after 100 h milling. Magnetization results suggest that a significant reduction of Fe magnetic moment occurs in the nano-crystalline Fe1-xCrx alloys. Curie temperature for x=0.46 and 0.69 lies below liquid N 2 and liquid He temperature, respectively

Exploring the micro-to-macro response of granular soils with real particle shapes via \u1d741\u1d46a\u1d47b-aided DEM analyses

This contribution provides high fidelity images of real granular materials with the aid of X-ray micro computed tomography (μCT ), and employs a multi-sphere approximation to reconstruct non-spherical particles. Through the discrete element method (DEM) simulations on granular samples composed of these non-spherical clumps, the effect of particle shape on the macroscopic mechanical response and microscopic soil fabric evolution is examined for sheared soil assemblies under triaxial loading conditions. Simulation results indicate that materials with more irregular particles tend to show higher shear resistance in both peak and critical stresses, while more sphere-like materials tend to exhibit lower void ratio and mean coordination number values under isotropic loading conditions and in the critical state. The proposed critical state parameters for describing the sensitivity of the mean coordination number to confining pressures are larger as particles become more irregular. At a microscopic level of observation, more irregular materials appear to exhibit higher fabric anisotropy in terms of contact normal and particle orientation in the critical state. The critical stress ratio determined through experimental and simulation results are found to be linearly linked to the shape-weighted fabric anisotropy index