GOALI:Deformation Mechanisms and Microstructure Evolution in Thermo-Mechanical Processing of Mg Alloys for Structural Automotive Applications

目标：汽车结构应用镁合金热机械加工中的变形机制和微观结构演变

• 批准号: 1006784
• 负责人: Surya Kalidindi
• 金额: $ 45万
• 依托单位: Drexel University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006784&HistoricalAwards=false
• 关键词: GOALI; Deformation; Mechanisms; Microstructure; Evolution

TECHNICAL SUMMARY: Although it has been widely observed that deformation twinning plays a dominant role in the deformation response of Mg alloys at room and elevated temperatures, its precise role on the ductility of these alloys is not yet understood. Establishing the physics of the underlying deformation mechanisms in Mg alloys has been complicated by many factors, including (i) the dramatic morphological and strain hardening rate differences between the two families of deformation twins observed in Mg alloys, (ii) the strong influence of grain size and temperature on the extent of deformation twinning, (iii) the activation of dynamic recrystallization during plastic deformation at elevated temperature, (iv) the activation of rotational dynamic recrystallization in some coarse-grained Mg alloys in certain temperature ranges, and (v) the potentially different influences of extension and contraction twins on the recrystallization processes. It is proposed to undertake a detailed experimental and modeling study to develop quantitative insights into the underlying deformation mechanisms in thermo-mechanical processing of two specific Mg alloys: AZ31 and Mg-0.2wt% Ce. Experimental investigations will include room and high temperature simple compression tests which will be interrupted for detailed microstructure investigations using orientation image microscopy and measurements of the local stored energy at the grain scale in plastically deformed samples. It is also proposed to develop and validate new physics-based elastic-viscoplastic crystal plasticity models to predict the anisotropic stress-strain response and the evolution of the microstructure in thermo-mechanical deformation of these alloys. These models will be subsequently employed to develop novel processing routes for cost-effective manufacture of structural automotive parts made from Mg alloys.NON-TECHNICAL SUMMARY: Strong but light magnesium (Mg) alloys offer tremendous potential for dramatic increases in the fuel efficiency of automobiles, with corresponding reductions in automotive CO2 emissions. The primary impediment to widespread application of these alloys is their very limited room temperature ductility, which prevents successful manufacture of the desired automotive structural components by standard inexpensive wrought processing methods. This proposal aims to produce the fundamental physical data sets and computational models of Mg alloy structure which are needed to find ways to improve the room temperature ductility of these alloys. The proposed interdisciplinary collaboration between researchers at Drexel University and at the General Motors Global R&D Center will result in the development of better Mg alloys for the automotive industry and may also have implications for the processing of other metals with similar crystalline structures. This project will produce two PhDs skilled in interdisciplinary research involving novel material characterization techniques, advanced computational mechanics, and applied mathematics. The project will expose numerous domestic undergraduate and graduate students, especially members of underrepresented groups in science and engineering, to cutting edge research methodologies and equipment.

技术摘要：尽管已广泛观察到，变形双胞胎在房间和温度升高的MG合金的变形响应中起主要作用，但其在这些合金延展性方面的精确作用尚未理解。许多因素使建立MG合金中潜在变形机制的物理学已经变得复杂，包括（i）在MG合金中观察到的两个变形双胞胎家族之间的戏剧性形态学和应变硬化速率差异，（ii）晶粒尺寸和温度的强大影响，（ii）在变形型塑料范围内的强大影响，（III）在（iii）的塑料范围内，（III）激活了激活的激活。在某些温度范围内，在某些粗粒的MG合金中旋转动态重结晶的激活，以及（v）延伸和收缩双胞胎在重结晶过程中的潜在影响。建议进行一项详细的实验和建模研究，以开发针对两种特定MG合金的热机械加工中潜在变形机制的定量见解：AZ31和MG-0.2WT％CE。实验研究将包括房间和高温简单压缩测试，这些测试将中断，以使用定向图像显微镜进行详细的微观结构研究，以及在晶粒尺度上以塑性变形的样品进行局部存储的能量的测量。还建议开发和验证新的基于物理学的弹性胶状晶体可塑性模型，以预测这些合金的热机械变形中微结构的各向异性应力 - 应变响应和微结构的演变。随后将采用这些模型来开发新颖的加工途径，以具有成本效益的由MG合金制成的结构性汽车零件制造。Non-Technical摘要：强但轻镁（MG）合金为汽车燃料效率的巨大增长提供了巨大的潜力，并具有相应的自动型销售量的燃料燃料效率。这些合金广泛应用的主要障碍是它们非常有限的室温延展性，这可以通过标准廉价的锻炼方法成功地制造所需的汽车结构组件。该建议旨在生产MG合金结构的基本物理数据集和计算模型，以找到改善这些合金室温延展性的方法。德雷克塞尔大学研究人员与通用汽车全球研发中心之间的拟议跨学科合作将导致为汽车行业开发更好的MG合金，并可能对处理具有类似晶体结构的其他金属的处理有影响。该项目将产生两项熟练的跨学科研究的博士学位，涉及新型材料表征技术，高级计算机械和应用数学。该项目将揭露许多国内本科生和研究生，特别是科学和工程领域的人为不足的团体的成员，以实现尖端的研究方法和设备。