Correlation between microstructure and residual stress in the additively manufactured products using advanced experimental characterizations

使用先进的实验表征，了解增材制造产品中微观结构和残余应力之间的相关性

• 批准号: 533273-2018
• 负责人: NUÑO, Natalia
• 金额: $ 1.82万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=661078
• 关键词: Correlation; between; microstructure; residual; stress

The concept of additive manufacturing (AM) in metallic materials such as steels, titanium alloys, and**biocompatible metals has gained enough attention to fabricate parts from easy to complex shape and geometry**more interestingly as semi-final or final products. The huge benefit from AM processes is to print the complete**shape of product in one step in contrary to conventional manufacturing processes where several steps are**required. The process has been developed over a few decades and it has become possible to produce 100%**dense bulk materials. In some industries such as marine industry and biomedical industry, certified products are**being fabricated. However, the mechanical properties may not meet the expectations in service due to complex**microstructure formed during AM processes. Due to repeated multiple thermal cycles induced by the**liquidation and solidification cycles applied to fabricate additive manufactured (AMed) products, different**level of recovery, local plastic deformation and structural discontinuities can be found in parts. As-fabricated**products own higher ultimate strength compared to their conventional versions but they show lower ductility**together with highly textured grains. This causes premature failure during mechanical evaluation. Therefore,**deep mechanical and metallurgical investigations are required to improve the part microstructures by**identifying the micro-mechanisms responsible for early failure and the solutions to improve mechanical**properties. The main objective of this project is described in the above explained context and aims to develop**an empirical model predicting the relationship between microstructural heterogeneities, residual strains**accumulated in the microstructure and resulted mechanical properties.

金属材料（例如钢、钛合金和**生物相容性金属）的增材制造（AM）概念已获得足够的关注，可以制造从简单到复杂形状和几何形状的零件**更有趣的是作为半成品或最终产品。增材制造工艺的巨大好处是一步即可打印出产品的完整**形状，这与需要多个步骤的传统制造工艺相反。该工艺经过几十年的发展，已经可以生产 100%** 致密的散装材料。在海洋产业、生物医药产业等一些行业，认证产品正在被制造出来。然而，由于增材制造过程中形成的复杂**微观结构，机械性能可能无法满足使用中的预期。由于用于制造增材制造 (AMed) 产品的**液化和凝固循环引起了重复的多个热循环，因此在零件中可能会发现不同**水平的恢复、局部塑性变形和结构不连续性。与传统版本相比，成品**产品具有更高的极限强度，但它们表现出较低的延展性**以及高度纹理化的颗粒。这会导致机械评估期间过早失效。因此，需要进行深入的机械和冶金研究，通过识别导致早期失效的微观机制以及改善机械性能的解决方案来改善零件的微观结构。该项目的主要目标在上述解释的背景下进行了描述，旨在开发**一个经验模型，预测微观结构不均匀性、微观结构中累积的残余应变**和最终的机械性能之间的关系。