The applicability of standard lattice percolation models to a random two-dimensional grain structure is explored. A random network based on the triangle lattice is proposed as a more appropriate model, and results in a higher percolation threshold (0.711 compared with 0.653 for the standard hexagonal lattice). The triple junction constraint inherent in grain boundary structures is subsequently ...

Classical overall transformation kinetics theory for grain boundary nucleated transformations relies on the assumption that the parent phase grain size is uniform. In the present work the theory is adapted to deal with the case where there is a distribution in the size of the parent grains, as is often found in practice. It is demonstrated that the overall transformation rate is fastest when th...

In this paper, the effect of alloy composition on the microstructural development of devitrified Nd–Fe–B-based alloys is investigated. While crystallization of simple ternary Nd2Fe14B resulted in a highly variable microstructure and relatively poor demagnetization behavior, alloying additions, notably Ti and C, were found to significantly refine and homogenize the crystallized microstructure. H...

In the frame of a long-term experiment carried out in Central Italy, conventional and organic winter wheat cropping systems were compared in 2004 and 2005 to evaluate the effect of system management on wheat grain yield and quality. The organic system showed grain and straw yield about 50% lower than the conventional system. Organic grain samples resulted 20% lower in protein content and exhibi...

This work addresses two transitions in material behavior: one, the initial peak in stress response associated with dynamic recrystallization and two, the rapid increase in grain growth rate associated with pore separation from grain boundaries. A criterion is derived that predicts the initial peak in stress response associated with dynamic recrystallization, and another criterion is derived tha...

The topic of reconstruction of polycrystalline microstructures is briefly reviewed. An example is given of using orientation maps to reconstruct digital microstructures with a representation of a polycrystal structure that includes crystallographic orientation information. The method uses packing of ellipsoids to approximate the grain structure, coupled with Voronoi tessellation. For the exampl...

In order to achieve a homogeneous starting material for the production of dense Si3N4 by post-sintering of RBSN, the morphological and chemical characteristics of the Si-starting powders as well as the pore structure of the Si-powder compacts have to be optimized. In this context, the influence of the grain size distribution on the micropore size distribution of the Sipowder compacts was determ...

The three-dimensional interfacial grain boundary network in a fully austenitic high-manganese steel was studied as a function of all five macroscopic crystallographic parameters (i.e. lattice misorientation and grain boundary plane normal) using electron backscattering diffraction mapping in conjunction with focused ion beam serial sectioning. The relative grain boundary area and energy distrib...

In this paper, the microstructure, the room-temperature and high-temperature tensile mechanical properties of monolithic TA15 alloy and TiB whisker-reinforced TA15 titanium matrix composites (TiBw/TA15) fabricated by vacuum hot-pressing sintering were investigated. The microstructure results showed that there were no obvious differences in the microstructure between monolithic TA15 alloy and Ti...