PNNL

Abstract

Every year, TMS Magnesium Committee carefully selects a special topic in magnesium (Mg) related research and development not only having the hottest subject from both academic and industrial perspectives but also demonstrating major achievements within this subject. Following last year’s topic on Mg microallying [1], this year’s focus is on in-situ methods and associated techniques in their broad definition spanning from laboratory- to large- scale facilities to process monitoring. The applications of in-situ techniques have a wide spectrum from the analysis of melts and liquid-solid transitions to solid-state phenomena during thermo-mechanical processing and heat treatments to surface interactions with various environments. Therefore, such works are of significant interest to scientists working in the area of Mg alloy development as well as to a much broader audience from both academia and industry. This interest is primarily caused by challenges in the analysis of structure-property relationship in Mg alloys, and even cursory glance of literature reveals sharp increase of publications relevant to this topic recently. For instance, very high reactivity of Mg as well as its well-known propensity to substantially alter structure upon unloading in mechanical testing makes it difficult to understand and thus to simulate correlation between microstructures observed in post-mortem analysis and physical processes during testing or fabrication. However, recent advances in in-situ analysis based on large-scale research facilities such as neutron scattering and synchrotron radiation sources as well as microscopy-based, acoustic emission, and other more traditional techniques allowed significant achievements. Apart from apparent development of relevant experimental techniques, a significant part of this success should also be attributed to increasing accessibility of the facilities and simplification of their use from a user perspective. The selection of articles in this special topic is quite far from comprehensive review covering all aspects of in-situ methods available for metallic materials development. However, this was not the purpose in any case. Instead, this selection is intended to present several studies on Mg alloys and Mg-based composites with the use of in-situ techniques. In addition, it overviews two techniques, ‘Acoustic Emission’ (AE) and ‘Ambient-Pressure X-ray Photoelectron Spectroscopy’ (AP-XPS), that are rather novel to the Mg community. These studies are supposed to give readers representative examples of such techniques potential and to help in navigating the spectrum of modern state-of-the-art analytical methods facilitating the development of Mg alloys. These articles are organized in the order corresponding to typical Mg alloy lifecycle from material preparation and solidification to thermo-mechanical processing and product fabrication to degradation.