Mechanical properties of thin wall specimens produced by additive manufacturing methods

增材制造（AM）技术为加拿大的经济和社会带来了新的机遇。它可以为包括航空航天和生物医学在内的许多部门生产坚固、轻便的产品，并且可以实现以前制造技术无法实现的设计。铝和钛合金对增材制造非常感兴趣，因为这些是相对昂贵的金属，增材制造可以最大限度地减少传统铸造、锻造和加工路线产生的材料浪费。对于薄壁的具体问题，随着截面尺寸的减小，表面敏感性（即表面光洁度）对其性能的影响要大得多。此外，由于特征尺寸较小，薄壁受到周围粉层更大的热耗散。因此，增材制造工艺产生的薄特征通常包括未熔化的粉末夹杂物、内部空隙、裂纹和形状不规则等缺陷。表面增材制造后处理技术通过去除和/或平滑表面，或诱导所需的表面形态或减少拉伸表面残余应力，解决与制造增材制造材料表面不规则形态和随机定位特征相关的问题。因此，这一合作伙伴关系的目标是了解粉末特性和增材制造工艺变量以及增材制造后处理对薄壁尺寸部件增材制造（AM）的影响，最终目标是能够设计出具有最理想特性的粉末，用于通过激光-粉末床融合（L-PBF）和粘合剂喷射工艺制造的增材制造。由于该项目将由2名博士生执行，另一个主要成果将是增加魁北克和加拿大的AM技术基础。该项目是麦吉尔大学、粉末制造公司a P and C和Nanogrande之间的合作项目。Nanogrande是一家加拿大的高分辨率3D打印机、金属3D零件制造商，也是第一家使用金属粉末的纳米增材制造技术的公司。这三家公司已经建立了紧密的合作关系，该项目将在此基础上建立。

Additive manufacturing (AM) technology opens new opportunities for the economy and society of Canada. It can facilitate the production of strong, light-weight products for many sectors, including aerospace and biomedical, and it allows designs that were not possible with previous manufacturing techniques. Aluminum and titanium alloys are of great interest for AM since these are relatively expensive metals and AM can minimize the waste of material that is generated by traditional casting, forging and machining routes. Regarding the specific problem of thin walls, as section size decreases, surface sensitivity, i.e., surface finish, is much more influential on the properties In addition, due to the small feature dimensions, the thin walls are subjected to more significant thermal dissipation from the surrounding powder beds. As a result, thin features generated by AM processes often include defects such as un-melted powder inclusions, internal voids, cracks, and shape irregularities. Surface post-AM-processing techniques tackle the issues associated with the irregular morphology and the randomly positioned features on the surface of as-built AM material, by removing and/or smoothing the surface, or inducing a desired surface morphology or reducing the tensile surface residual stress. The goal of this partnership is therefore to understand the effect of powder characteristics and AM process variables and post AM build treatments on the additive manufacturing (AM) of components with thin wall dimensions, the ultimate goal being to be able to design powders with the most desirable characteristics for such AM builds made by laser- powder bed fusion (L-PBF) and binder jet processes. Since this project will be performed by 2 Ph.D. students, another major outcome will be to increase the AM technological base in Quebec and Canada. The project is a collaboration between McGill University, A P and C, a powder manufacturing company, and Nanogrande, a Canadian based manufacturer of high-resolution 3D printers, metal 3D parts and the first with nano additive manufacturing technology with metal powders. All three already enjoy strong collaborations and this project will readily build on this foundation.