Understanding plastic instability in next generation magnesium alloys

了解下一代镁合金的塑性不稳定性

• 批准号: 420149269
• 负责人: Dr.-Ing. Talal Al-Samman
• 金额: --
• 依托单位: Institut für Metallkunde und Metallphysik (IMM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/420149269?language=en
• 关键词: Understanding; plastic; instability; next; generation

In alloy and process design endeavours of highly formable wrought Mg alloys it is utterly important to account for material instability that occurs during plastic deformation. Especially, unwanted associated effects, such as strain localization, premature cracking and surface striations, should be avoided by understanding their mechanistic origins over a wide range of deformation conditions. Therefore, the present research proposal focuses on better understanding the link between dynamic microstructural phenomena, such as dynamic recovery, dynamic recrystallization and dynamic precipitation and the occurrence of plastic instability as a function of varying deformation conditions and alloy compositions. The main aims of the proposed project are to investigate the plastic flow instability (discontinuous yielding) in selected Mg-Mn-Nd and Mg-Mn-Ca alloys showing a good property profile of strength and formability, and provide a sound description of the governing mechanisms of plastic instability in the investigated alloys. Additionally, the conditions under which the plastic instability occurs as a result of presence of solute atoms and/or precipitates, and their interaction with mobile dislocations will be determined. Also of importance is whether possible synergetic effects of alloying elements play an increasing role in the onset of plastic instability, as compared to individual alloying additions, and whether such effects can be exploited to optimise texture and microstructure.The proposed research is of fundamental nature but has significant implications for sheet metal forming perspectives, particularly in the automotive and aircraft industries, where Mg alloys, due to their excellent specific strength, are becoming increasingly important. Acquiring advanced knowledge of the correlation between alloy composition, active deformation mechanisms and the occurrence of plastic instability greatly contributes towards improving the performance of next generation magnesium alloys by increasing their strength and forming capability.

在高度可成形的变形镁合金的合金和工艺设计中，考虑在塑性变形期间发生的材料不稳定性是非常重要的。特别是，不必要的相关影响，如应变局部化，过早开裂和表面条纹，应避免通过了解其在广泛的变形条件下的机械起源。因此，本研究建议的重点是更好地了解动态微观组织现象之间的联系，如动态回复，动态再结晶和动态析出和塑性不稳定性的发生作为不同的变形条件和合金成分的函数。该项目的主要目的是研究所选Mg-Mn-Nd和Mg-Mn-Ca合金的塑性流动不稳定性（不连续屈服），这些合金具有良好的强度和成形性，并对所研究合金的塑性不稳定性的控制机制进行了合理的描述。此外，将确定由于溶质原子和/或沉淀物的存在以及它们与移动的位错的相互作用而发生塑性不稳定性的条件。同样重要的是，与单独的合金添加剂相比，合金元素的可能的协同效应是否在塑性不稳定性的发生中发挥越来越大的作用，以及这种效应是否可以被利用来优化织构和微观结构。由于其优异的比强度，正变得越来越重要。获得合金成分、主动变形机制和塑性不稳定性发生之间的相关性的先进知识，通过提高下一代镁合金的强度和成形能力，大大有助于改善其性能。