Three-dimensional reconstruction of microstructure in AA5754 aluminum alloy and its welded joints

Microstructures of polycrystalline materials are three-dimensional in nature. In order to delineate the relationship of microstructure and mechanical properties of materials, it is very useful if one can generate a set of three dimensional virtual microstructures based on two dimensional experimental observations (e.g. optical micrographs) with reasonable assumptions, thus providing the possibility in changing the character of microstructures such as particulate morphology, size distribution and contiguity numerically. Several frameworks have been developed in recent years using statistical mechanics methods [1-4]. In this paper, an algorithm based on pair correlation functions (PCFs) [3-4] has been utilized to characterize and reconstruct three-dimensional microstructures in AA5754 automotive aluminum alloy and its plasma arc and Nd:YAG laser tailor welded blank joints. PCFs are quantified and discussed in detail for three orthogonal sections of microstructures in base metal, heat-affected zone (HAZ) and weldment. Three-dimensional virtual microstructures in the form of ellipsoids are then reconstructed for each region of the welded joint that targets to mimic the experimental PCFs on the corresponding section. The generated virtual microstructure could be directly used for numerical analysis (e.g. finite element method) in delineating a quantitative microstructure-mechanical properties relationship. Copyright © 2009 ASM International® All rights reserved.