Engineering of microstructures

Abstract

Structure is at the heart of the materials science paradigm connecting processing with properties. In the hierarchy of structures that exist in materials microstructure offers the richest variety of structural arrangements. This variety is often conveniently accessible, e.g., simply by heat treatment or mechanical deformation. Exploration of the relation between properties and microstructure serves to establish a target range of microstructural states that will perform. In order to attain a target microstructure it is necessary to understand what microstructures are, and how they evolve in processing. This presentation focuses upon the set of tools that must be combined to achieve this control:1. Geometry 2 Thermodynamics 3. Kinematics 4. Kinetics. The content of these tools is reviewed briefly and their uses illustrated in developing an understanding of how microstructures evolve. In this development an attempt is made to carry the description of each microstructural process as far as possible without making simplifying assumptions. The study of microstructures with this rigorous point of view was termed by F.N. Rhines, "microstructology".

Subgrain-controlled grain growth in the laser-melted 316 L promoting strength at high temperatures

“…One important aspect of the microstructure is the size of the grains and its influence on the properties. Thus, in order to design the grain size and restrict grain growth, microstructural engineering has become of fundamental importance [ 4 ]. The boundary between one grain and its neighbours (grain boundary) is a defect in the crystal structure and is associated with a certain amount of energy.…”

Topological Approach to Ferrite/Martensite Dual-phase Microstructures

“…2,3,17,18) The average and the product of the two principal curvatures are given by where H and K denote the mean and Gaussian curvatures, respectively. The mean curvature is related to the composition at the interface of a two-phase alloy; thus, it is an important parameter in microstructure evolution.…”

“…In materials science, it is well-known that morphology of microstructures plays a vital role on properties of materials. 2,3) For example, geometrical arrangement of martensite in a martensite-ferrite dual-phase (DP) steel affects the deformation and fracture behavior of the steel in addition to the yield strength ratio between martensite and ferrite, 4) the volume fraction of martensite, 5,6) and grain size. 6,7) It has been reported that a work-hardening rate becomes larger and fracture mode becomes brittle when ferrite is surrounded by honeycombed martensite, whereas uniform elongation becomes higher when ferrite is accompanied by dispersed martensite.…”

“…14,15) In addition to an assessment of the metric features, a topological assessment has been used to evaluate the dispersivity and connectivity of multi-phase microstructures. 2,3) On the other hand, the local morphology can be examined by curvature.…”

Determination of the synthetic hydroxyapatite life circle used in dental practice

“…According to the basic postulates of stereology [9][10][11], the surface and volume distribution of a measured/determined morphological parameter are mutually equal in the first approximation. According to the basic postulates of stereology [9][10][11], the surface and volume distribution of a measured/determined morphological parameter are mutually equal in the first approximation.…”