Microstructure modelling for metallic additive manufacturing: a review

Abstract

The microstructure of metal built using AM is highly dependent on the process parameters. However, experimentation on different process parameters for different materials is costly and time consuming. To overcome these challenges, numerical simulations provide insights that allow prediction of microstructure formed under different process parameters. Microstructure modelling requires coupling of macro-scale thermal model or experimentally measured temperature profiles with either a meso-scale or micro-scale microstructure model. In this review, the commonly used AM techniques for metals are introduced, followed by discussion on the microstructure of parts fabricated using these processes. This review then presents the latest models used in simulating different microstructural aspects of metal AM parts. In addition, the models were compared and the potential and challenges in microstructure modelling were discussed.

Hierarchical Microstructure of Laser Powder Bed Fusion Produced Face-Centered-Cubic-Structured Equiatomic CrFeNiMn Multicomponent Alloy

“…Equiaxed cells (magnified in Figure 3 d) are found relatively far from the melt pool boundaries, while elongated cells (magnified in Figure 3 e) are distributed close to the melt pool boundaries and appear approximately perpendicular to the boundaries, which are formed in the beginning of solidification due to epitaxial growth. The formation of these two types of cells is ascribed to the different temperature gradient and solidification velocity at the solid–liquid interface in different locations of the melt pool, especially at the edge or the bottom [ 30 ]. Nano-inclusions are more likely to be embedded at cell walls ( Figure 3 d,e).…”

Automatic determination of part build orientation for laser powder bed fusion

“…Although several existing part orientation methods, such as the methods of Zhang et al (2016), Brika et al (2017), Cheng and To (2019) and Raju et al (2019), have considered some of these factors, the estimation models in them are either not for the LPBF process or incomplete. From other existing literature, such as the articles of Bartolomeu et al (2016), Mukherjee, Zhang, and DebRoy (2017), Vastola, Pei, and Zhang (2018), Li et al (2019) and Tan, Sing, and Yeong (2020), some related estimation models can be found. However, build orientation is not a variable in these models.…”

Topological Design of a Trabecular Bone Structure With Morphology and Mechanics Control for Additive Manufacturing

“…Skeletal reconstruction of bone defects for load-bearing application is still a major challenge in orthopedic surgery. Solid metals and alloys such as stainless steel and titanium (Ti) have been successfully employed as bone implants owing to their excellent mechanical and bio-logical properties [1]. However, stress-shielding and impermeability have limited their applications [2].…”