It is hard to believe that a week from today we will not only be in the month of February, but also past that mid-winter holiday all of us weather-watchers look forward to (whether with hope, or dread, or, perhaps, trepidation). We shall roll past Ground Hogs Day next Wednesday. We usually trot out Booky our prognosticating badger on that day to challenge Punxsutawney Phil and Sun Prairie's Jimmy the Ground Hog. Our Booky has proved a remarkably accurate forecaster so you may want to watch our social media for his prediction. Unlike his fellow predictors of the remaining length of winter who get up at the crack of dawn, Books prefers to wake up gently, have his cup of coffee, read the newspaper, and then step outside to see what day might hold. Even if all three of these animal forecasters predict an extended winter season you can be sure of a couple of things. First, that no matter how long the winter weather persists, the Winter Reading Program will end on the first day of spring by March 20th. The second thing you can be sure of is that while the days are getting longer there is still prime reading time to be had in the evenings (and mornings too). And finally, there are plenty of new books for you to peruse, skim, and dig into. Below are some of the new titles which recently arrived at the library. Enjoy!
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Recently developed Al-Li-Cu alloys show great potential for implementation in the aerospace industry because of the attractive mix of good mechanical properties and low density. AA2099 is an Al-Li-Cu alloy with the following composition Al-2.69wt%Cu-1.8wt%Li-0.6wt%Zn-0.3wt%Mg-0.3wt%Mn-0.08wt%Zr. The environmental assisted cracking and localized corrosion behavior of the AA2099 was investigated in this thesis. The consequences of uncontrolled grain boundary precipitation via friction stir welding on the stress corrosion cracking (SCC) behavior of AA2099 was investigated first. Using constant extension rate testing, intergranular corrosion immersion experiments, and potentiodynamic scans, the heat-affected zone on the trailing edge of the weld (HTS) was determined to be most susceptible of the weld zones. The observed SCC behavior for the HTS was linked to the dissolution of an active phase (Al2CuLi, T1) populating the grain boundary. It should be stated that the SCC properties of AA2099 in the as-received condition were determined to be good. Focus was then given to the electrochemical behavior of precipitate phases that may occupy grain and sub-grain boundaries in AA2099. The grain boundary micro-chemistry and micro-electrochemistry have been alluded to within the literature as having significant influence on the SCC behavior of Al-Li-Cu alloys. Major precipitates found in this alloy system are T1 (Al 2CuLi), T2 (Al7.5Cu4Li), T B (Al6CuLi3), and theta (Al2 Cu). These phases were produced in bulk form so that the electrochemical nature of each phase could be characterized. It was determined T1 was most active electrochemically and theta was least. When present on grain boundaries in the alloy, electrochemical behavior of the individual precipitates aligned with the observed corrosion behavior of the alloy (e.g. TB was accompanied by general pitting corrosion and T 1 was accompanied by intergranular corrosion attack). In addition to the electrochemical behavior of 2ff7e9595c
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