Effect of Rare Earth Upon As-Cast Microstructure and High Temperature Performance of ZA40 Alloy
In testing comparison, this study is made on the modification effect of 0.05 wt.% La-rich rare earth (RE) upon as-cast microstructure, mechanical properties of materials at high temperatures (100, 150, 200°C) and wear resistance under different temperatures (100and 200°C) of ZA40 alloy containing Si. The addition of RE shows that it can not only effectively refine Al-rich and Cu-rich phase, but also reduce the amount of needle-like eutectic silicon, and then make the size of massive primary silicon phase smaller. Thus, there are the improvement of strength, ductility and wear resistance of materials at high temperature. The analyses are also conducted on the mechanism of underlying RE elements.
Hot deformation and processing map of ZA27 alloy
The hot deformation behavior of ZA27 alloy were investigated by compressive tests on Gleeble-1500 thermal-mechanical simulating tester in the temperatures range of 200-350 ℃,strain rate range of 0.01-5 s-1 and engineering strain of 60%.Based on Murty criterion,the processing map for the ZA27 alloy was obtained.The results show that the flow stress decreases with the increase of temperature,while increases with the increase of strain rate.The flow instability regimes appear at two different regimes: at the temperature of 200-210 ℃and the strain of 0.01-0.1 s-1,as well as at the temperature of 250-350 ℃ and the strain rate of 1-5 s-1.The dynamic recrystallization is the main reason for flow softening and stable flow.The hot deformation of ZA27 alloy can be carried out safely in the region with a strain rate of 0.1-1 s-1 and temperature range of 250-350 ℃.
The Bastille: A History of a Symbol of Despotism and Freedom
This book is both an analysis of the Bastille as cultural paradigm and a case study on the history of French political culture. It examines in particular the storming and subsequent fall of the Bastille in Paris on July 14, 1789 and how it came to represent the cornerstone of the French Revolution, becoming a symbol of the repression of the Old Regime. Lusebrink and Reichardt use this semiotic reading of the Bastille to reveal how historical symbols are generated; what these symbols’ functions are in the collective memory of societies; and how they are used by social, political, and ideological groups.

To facilitate the symbolic nature of the investigation, this analysis of the evolving signification of the Bastille moves from the French Revolution to the nineteenth century to contemporary history. The narrative also shifts from France to other cultural arenas, like the modern European colonial sphere, where the overthrow of the Bastille acquired radical new signification in the decolonization period of the 1940s and 1950s. The Bastille demonstrates the potency of the interdisciplinary historical research that has characterized the end of this century, combining quantitative and qualitative approaches, and taking its methodological tools from history, sociology, linguistics, and cultural and literary studies.