Reduction of plastic anisotropy and improved formability of novel magnesium alloy sheets through utilization of Equal-Channel Angular Pressing (ECAP)

通过等通道角向压制 (ECAP) 降低新型镁合金板材的塑性各向异性并提高成型性

• 批准号: 455383045
• 负责人: Dr. José Victoria-Hernández
• 金额: --
• 依托单位: Helmholtz-Zentrum hereon GmbH
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/455383045?language=en
• 关键词: Reduction; plastic; anisotropy; improved; formability

The main objective of this project is to understand the physical mechanisms involved during warm forming and provide guidelines to significantly reduce the anisotropy while maintaining the good formability of magnesium Mg-Zn-RE and Mg-Zn-Ca alloy sheets. Both alloy systems are known by the good stretch formability even at room temperature. The analysis and improvement of mechanical and forming behavior of both alloy systems are scientific and application oriented relevant. With special emphasis in the Mg-Zn-Ca system, which does not use the strategic RE elements, applications in the automotive industry and biomedical sector are feasible within the near future. However due to the distinctive texture development after conventional rolling and annealing, they show strong anisotropic deformation and forming behavior, i.e. significantly difference in the work hardening rate (WHR) along different directions with respect to RD and development of strong earing after deep drawing. In this regard, this project deals with the processing of Mg sheets by means of severe plastic deformation to use the potential of texture engineering via shear strain. Preliminary works already showed that with Equal-Channel Angular Pressing (ECAP) for sheet metal, it is feasible to enhance the mechanical behavior of Mg-Zn-RE alloy. The utilization of this unique process can serve to systematically tailor the crystallographic texture of the workpiece to investigate its effect on the forming behavior at temperatures below 200 °C. In addition to this, coupled finite element (FEM) and crystal plasticity (CP) simulations are proposed not only to provide a sound understanding on ways to tailor the crystallographic texture during ECAP processing, but also give insights in the effect of the activation of slip and twinning modes during forming tests. It is important to highlight that both alloy systems are known by limited dynamic recrystallization during forming at temperatures below 200 °C, which will allow a rather good prediction of the simulated plastic activity of deformation mechanisms. The validation of the mechanical and forming properties will then be carried out at different temperatures and strain rates close to practical application. Such a detailed validation will prove the functionality of these basic investigations and will provide guide lines to reduce the anisotropy of these formable alloys. At the end of the funding period, a state of knowledge is to be developed that will allow the production of an high formable and texture reduced magnesium sheet using tailor-made sub-processes, thus opening up the use of magnesium for other sub-sectors and achieving further progress in the field of lightweight construction.

本项目的主要目的是了解温成形过程中涉及的物理机制，并提供指导方针，以显着降低各向异性，同时保持良好的成形性镁合金Mg-Zn-RE和Mg-Zn-Ca板材。这两种合金系统都已知即使在室温下也具有良好的拉伸成形性。分析和改进这两种合金体系的力学性能和成形性能具有科学性和实用性。特别强调Mg-Zn-Ca系统，它不使用战略RE元素，在汽车工业和生物医学领域的应用是可行的，在不久的将来。然而，由于在常规轧制和退火之后的独特织构发展，它们显示出强烈的各向异性变形和成形行为，即，在加工硬化速率（WHR）上沿相对于RD的沿着不同方向的显著差异以及在深冲之后的强制耳发展。在这方面，本项目涉及通过剧烈塑性变形来利用通过剪切应变进行织构工程的潜力来处理Mg片材。初步研究表明，采用双通道转角挤压（ECAP）技术提高Mg-Zn-RE合金的力学性能是可行的。利用这种独特的工艺可以系统地定制工件的晶体织构，以研究其在低于200 °C的温度下对成形行为的影响。除此之外，耦合有限元（FEM）和晶体塑性（CP）模拟提出不仅提供了一个良好的理解的方式来定制的晶体织构在ECAP加工过程中，但也给出了洞察力的激活的效果的滑移和孪生模式在成形试验。重要的是要强调的是，这两种合金系统都是已知的，在低于200 °C的温度下成形期间的有限动态再结晶，这将允许相当好地预测变形机制的模拟塑性活动。然后将在接近实际应用的不同温度和应变速率下对机械和成形性能进行验证。这种详细的验证将证明这些基本研究的功能，并将提供指导方针，以减少这些可成形合金的各向异性。在资助期结束时，将开发一种知识状态，允许使用定制的子工艺生产高度可成形和纹理减少的镁板，从而为其他子行业开辟镁的使用，并在轻质建筑领域取得进一步进展。