Developing new metallic alloys for Additive Manufacturing

加拿大制造业占GDP的10%，占劳动力的近10%(加拿大统计局)。加法制造(AM)，或3D打印，是一种新的制造方法，将三维组件逐层构建成复杂的3D零件。这种制造方法与传统制造业有很大的不同。通常情况下，零件经过设计和铸造，然后进行冷热加工、热处理和机械加工。AM为重新设计组件提供了创新的新机会。AM正在经历戏剧性的增长，2017年增长超过21.5亿美元，行业整体增长21%。必须开发新的金属合金，以满足迄今为止被认为不可能制造的部件的创新设计的特殊需要。创新的设计包括在AM组件中使用桁架网格。这使得具有尚未用于工程应用的新型成分的粉末合金的使用成为可能。铝铜合金(Al-Cu)就是一个例子，传统上，由于重量轻和强度增加，铜含量被限制在~4.5wt%。随着AM的桁架设计的出现，可以使用铜含量更高的合金，同时生产密度比传统整体材料更轻的部件，并在强度上有相当大的提高。建议从研究共晶和近共晶成分的Al-Cu和Al-Ni开始这一计划。最初感兴趣的是共晶形成的工艺条件。随后，将研究通过时效使共晶的金属间化合物成分球化的能力。然后，这些粉末将与UofA Mech E Qureshi教授合作用于AM设备。这将刺激由工业和NSERC资助的使用这些新型粉末制造AM组件的新项目。利用扫描电子显微镜、中子散射和三维显微层析技术对共晶组织进行了定量表征。球状金属间化合物的演化将在Ho和Weatherly之后定义。将使用定量图像分析和机器学习技术来测量金属间颗粒之间的间距及其大小。最后，这些测量将与对老化样品进行的维氏显微硬度测量相关。四名研究生将接受为期5年的培训。其中两个将处理铝铜问题，两个将处理铝镍问题。一组两名学生将讨论该项目的快速凝固方面，而另外两名学生将讨论粉末的老化过程。这将为所有4名学生提供进行高温实验、表征方法、3D显微层析成像、定量金相以及合金凝固路径的建模以及凝固形成的微观组织与所产生的性能之间的关系的培训。这项建议中所描述的努力为我们的研究带来了新的推动力。

Canadian manufacturing accounts for 10% of GDP and nearly 10% of the labour force (Statistics Canada). Additive manufacturing (AM), or 3D printing, is a new manufacturing approach where three dimensional components are built layer by layer forming a complex 3D part. This manufacturing approach deviates significantly from traditional manufacturing. Typically, components are designed and cast followed by hot and cold working, heat treatment and machining. AM provides innovative new opportunities for re-designing components. AM is undergoing a dramatic rise expanding in 2017 by more than $2.15 billion and a 21% overall growth in the industry. New metallic alloys must be developed to meet the special needs for innovative designs of components hitherto thought impossible to make. Innovative designs include the use of truss lattices in AM components. This enables the use of powdered alloys with novel compositions not yet used for engineering applications. Aluminum-copper alloys (Al-Cu) is one example, where traditionally the copper content is limited to ~4.5wt% due to light-weighting goals and increased strength. With the advent of truss designs for AM, higher copper content alloys may be utilised while producing components with lighter densities than traditional monolithic materials and with a considerable increase in strength. It is proposed to begin this program by studying Al-Cu and Al-Ni of eutectic and near-eutectic compositions. Of initial interest is the process conditions under which eutectics form. Subsequently, the ability to spheroidize the intermetallic constituent of the eutectic by aging will be studied. The powders will then be used in AM equipment in collaboration with Prof Qureshi, Mech E UofA. This will stimulate new projects funded by industry and NSERC using these novel powders in making AM components. The eutectic microstructures will be quantitatively characterized using scanning electron microscopy, neutron scattering and 3D micro-tomography. The evolution of spherical intermetallics will be defined following Ho and Weatherly. The spacing between intermetallic particles and their size will be measured using quantitative image analysis and machine learning techniques. Finally, these measurements will be related to Vickers micro hardness measurements to be made on aged samples. Four graduate students will be trained over the duration of 5 years. Two will tackle Al-Cu and two Al-Ni. One set of two students will address the rapid solidification aspects of the project while the other two will address the ageing processing of the powders. This will provide all 4 students training in the conduct of high temperature experiments, characterisation methods, 3D microtomography, quantitative metallography as well as modelling of solidification paths of alloys and the relationship between solidification-developed microstructure and resulting properties. The effort described in this proposal initiates a new thrust in our research.