Increasing the formability of magnesium alloy sheet

镁的主要优势是密度远低于铝，板状镁合金是增加汽车使用量的主要途径之一。然而，使用镁薄板的问题是其室温成形性低，可以通过添加适当的合金元素和/或不同的制板和制件方法来克服这一问题。这项建议研究了三种提高板材成形性的方法：(I)添加稀土元素(REE)和钙；(Ii)对轧制的板材进行专门的热处理，以便在成形部件之前适当软化板材；以及(Iii)在部件成形操作期间软化板材。稀土在改善轧制镁组织中的作用是众所周知的，但还不是很清楚，而且还远未得到优化。因此，这项工作将包括一个原子水平的计算方法，以了解稀土和钙的影响，以便设计稀土轴承合金与贫化。专门的热处理方法需要专门的轧制来制造薄板。因此，将研究板材轧制和后续热处理之间的相互作用，并对其进行建模，以最大化成形性。最后，在从板材成形部件的过程中，板材的软化以前从未被考虑过，但之所以成为可能，是因为目前的成形方法使板材处于‘温暖’的温度(约200摄氏度)，这开辟了一些真正新颖的成形方法。

The chief advantage of magnesium is a density that is much lower than aluminum and Mg alloy in sheet form is one of the main routes to increased usage in cars. However, the problem of using Mg sheet is its low room temperature formability, which could be overcome by adding suitable alloying elements and/or different approaches to making sheet and making components out of sheet. This proposal investigates three approaches to increasing sheet formability: (i) additions of neodymium, a rare earth element (REE), and calcium; (ii) specialized heat treatments of rolled sheet to appropriately soften the sheet before forming the component and (iii) softening the sheet during the component forming operation. The effect of REE in improving the microstructure of rolled Mg is well known but not well understood and far from optimised. Thus, this work will include an atomic level computational approach to understand the effects of REE and Ca, in order to design REE bearing alloys with lean chemistries. The specialized heat treatment approach needs specialized rolling to make the sheet. Therefore, the interplay between sheet rolling and subsequent heat treatment will be studied and modelled to maximise formability. Finally, softening of the sheet during the forming of a component from the sheet has never before been considered, but is made possible because the current forming approach subjects sheet to 'warm' temperatures (about 200 centigrade), and this opens up some really novel approaches to forming.